Answer:
1. Y= 7t^5 +C
2. Y= 35/12x^(12/7)+C
Step-by-step explanation:
The general solution will be determined by integrating the equations as the integration is a simple integration.
For dy/dt = 35t^4
The general solution y
= integral (35t^4)dt
The general solution y
=( 35/(4+1))*t^(4+1)
= 35/5t^5
= 7t^5 +C
To prove by differentiating the above.
Y= 7t^5 +C
Dy/Dt= (5*7)t^(5-1) +0
Dy/Dt= 35t^4
For dy/dx = 5x^(5/7)
Y=integral 5x^(5/7)Dx
Y= 5/(5/7 +1)*x^(5/7+1)
Y= 5/(12/7) *x^(12/7)
Y= 35/12x^(12/7)+C
To prove by differentiating
Y= 35/12x^(12/7)+C
Dy/Dx= (35/12)*(12/7) x^(12/7-1) +0
Dy/Dx=(35/7)x^(5/7)
Dy/Dx= 5x^(5/7)
The General Social Survey (GSS) is a sociological survey used to collect data on demographic characteristics and attitudes of residents of the United States. In 2010, the survey collected responses from over a thousand US residents. The survey is conducted face-to-face with an in-person interview of a randomly-selected sample of adults. One of the questions on the survey is "For how many days during the past 30 days was your mental health, which includes stress, depression, and problems with emotions, not good?" Based on responses from 1,151 US residents, the survey reported a 95% confidence interval of 3.40 to 4.24 days in 2010. Given this information, which of the following statements would be most appropriate to make regarding the true average number of days of "not good" mental health in 2010 for US residents? 1 point For these 1,151 residents in 2010, we are 95% confident that the average number of days of "not good" mental health is between 3.40 and 4.24 days. There is not sufficient information to calculate the margin of error of this confidence interval. For all US residents in 2010, based on this 95% confidence interval, we would reject a null hypothesis stating that the true average number of days of "not good" mental health is 5 days.
The most appropriate statement is the one that correctly reflects the confidence interval obtained from the survey data, as stated above.
The most appropriate statement to make regarding the true average number of days of "not good" mental health in 2010 for US residents, based on the given information, is:
"For these 1,151 residents in 2010, we are 95% confident that the average number of days of 'not good' mental health is between 3.40 and 4.24 days."
The 95% confidence interval of 3.40 to 4.24 days is obtained from the survey data, and it provides an estimate of the range within which the true average number of days of "not good" mental health falls for the entire population of US residents.
Regarding the provided options:
There is not sufficient information to calculate the margin of error of this confidence interval: This statement is not accurate since the margin of error can be calculated using the formula Margin of Error = (Upper Limit - Lower Limit) / 2.
For all US residents in 2010, based on this 95% confidence interval, we would reject a null hypothesis stating that the true average number of days of "not good" mental health is 5 days: This statement is not supported by the given information. The confidence interval provides an estimate of the range within which the true average lies, but it does not involve a comparison to a specific value such as 5 days.
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Based on the provided information and the 95% confidence interval of 3.40 to 4.24 days for "not good" mental health in 2010,
The most appropriate statement to make regarding the true average number of days of "not good" mental health for US residents in 2010 is:
"For these 1,151 residents in 2010, we are 95% confident that the average number of days of 'not good' mental health is between 3.40 and 4.24 days."
This statement accurately represents the confidence interval obtained from the survey data.
It indicates that the true average number of "not good" mental health days for the entire US population in 2010 is likely to fall within this range with a 95% level of confidence.
It's important to note that this statement only applies to the specific sample of 1,151 US residents surveyed in 2010.
To make inferences about the true average number of "not good" mental health days for all US residents in 2010, a different sample with a larger representative size would be required.
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3) The average age of students at XYZ University is 24 years with a standard deviation of 8 years. Number of students at the university is 7500. A random sample of 36 students is selected. What is the probability that the sample mean will be between 25.5 and 27 years
Answer:
0.1875
Step-by-step explanation:
σM=σ/√N
=8/√7500
=8/86.608
=0.092
Z=(x-μ)/σ/√N
=(25.5-36)/8/√7500
=-10.5/0.0092=-1141.304
Z score = -1.3125
=(27-36)/8/√7500 =
=9/0.0092=978.261
Z score= -1.125
-1.125-(-1.3125)=-1.125+1.3125)= 0.1875
The probability that the sample mean will be between 25.5 and 27 years
P(between 25.5 and 27) = 0.1875
What is the radius of a circle given by the equation x2 + y2 – 2x + 8y – 47= 0? radius = units
Answer:
8 units
Step-by-step explanation:
We need to rewrite an equation in the standard for a circle form.
r is radius.
(x−h)²+(y−k)²= r²
x² + y² – 2x + 8y – 47= 0
x² - 2x + y² + 8y - 47 = 0
x² - 2*x *1+ 1 ²- 1² + y² + 2*4*y + 4² - 4² - 47 = 0
(x - 1)² + (y + 4)² - 1 - 16 -47 =0
(x - 1)² + (y + 4)² - 64=0
(x - 1)² + (y + 4)² = 8²
Radius is 8.
The radius of the circle is 8 units
What is radius?The radius of a circle is a line drawn from the center to the circumference of the circle
The equation of the circle is given as;
[tex]x^2 + y^2 - 2x + 8y - 47 = 0[/tex]
Rewrite the equation as:
[tex]x^2 - 2x + y^2 + 8y = 47[/tex]
Next, we rewrite the equation in the standard form
So, we have:
x^2 - 2x + 1^2 - 1^2 + y^2 + 8y + 4^2 - 4^2 = 47
Evaluate the exponents
x^2 - 2x + 1 - 1 + y^2 + 8y + 16 - 16 = 47
Rewrite the equation as follows:
x^2 - 2x + 1 + y^2 + 8y + 16 = 47 + 1 + 16
Express as perfect squares
(x - 1)² + (y + 4)² = 64
(x - 1)² + (y + 4)² = 8^2
The radius of the circle is calculated as:
r^2 = 8^2
By comparison, we have:
r = 8
Hence, the radius of the circle is 8 units
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Find the rate of change of total revenue, cost, and profit with respect to time. Assume that R(x) and C(x) are in dollars. R(x)equals60 x minus 0.5 x squared, C(x)equals3 x plus 5, when xequals40 and dx divided by dtequals15 units per day
Answer:
Step-by-step explanation:
Given the Revenue in dollars modelled by the function R(x) = 60x-0.5x²
Cost in dollars C(x) = 3x+5
Profit function = Revenue - Cost
P(x) = R(x) - C(x)
P(x) = 60x-0.5x²-(3x+5)
P(x) = 60x-0.5x²-3x-5
P(x) = -0.5x²+57x-5
The rate of change of total revenue = dR(x)/dt
dR(x)/dt = dR(x)/dx * dx/dt
dR(x)/dx = 60-2(0.5)x²⁻¹
dR(x)/dx = 60-x
Given x = 40 and dr/dx = 15 units per day
dR(x)/dt = (60-x)dx/dt
dR(x)/dt = (60-40)*15
dR(x)/dt = 20*15
dR(x)/dt = 300dollars
Rate of change of revenue = 300dollars
For the rate of change of cost;
dC(x)/dt = dC(x)/dx * dx/dt
dC(x)/dt = 3dx/dt
dC(x)/dt when dx/dt = 15 will give;
dC(x)/dt = 3*15
dC(x)/dt = 45 dollars.
Rate of change of revenue = 45dollars
For the profit;
Profit = Rate of change of revenue - rate of change of cost
Profit made = 300-45
profit made = 255 dollars
Find the slope of the line passing through the points (-3, -8) and (4,6).
Answer:
slope = 2Step-by-step explanation:
The formula of a slope:
[tex]m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
We have
[tex](-3;\ -8)\to x_1=-3;\ y_1=-8\\(4;\ 6)\to x_2=4;\ y_2=6[/tex]
Substitute:
[tex]m=\dfrac{6-(-8)}{4-(-3)}=\dfrac{6+8}{4+3}=\dfrac{14}{7}=2[/tex]
The formula for the slope m of the line that passes through two points [tex](x_1, y_1)[/tex] and [tex](x_2, y_2)[/tex] is the following:
[tex]m=\dfrac{y_1-y_2}{x_1-x_2}[/tex]
We have points (4,6) and (-3,-8). Let's plug these values into the formula for slope:
[tex]m=\dfrac{6-(-8)}{4-(-3)}[/tex]
[tex]=\dfrac{14}{7}=2[/tex]
The slope of the line passing through the two points is 2. Let me know if you need any clarifications, thanks!
Yo tenía $5
Mi mamá me dió $10
Mi papá me dió $30
Mi tío y mi tía me dieron $100
Yo tenía otros $20
¿Cuánto tenía?
Answer:
$25
Step-by-step explanation:
De la pregunta anterior, se nos da la siguiente información
Yo TENÍA $ 5
Mi mamá me dió $ 10
Mi papá me dió $ 30
Mi tío y mi tía me dieron $ 100
Yo TENÍA otros $ 20
Si miras arriba, notarás que la palabra TENÍA está en mayúscula.
Esto se debe a que para resolver esta pregunta correctamente, tenemos que concentrarnos o prestar atención a los tiempos verbales del inglés que se usan al hacer la pregunta.
La pregunta dice: ¿Cuánto tenía?
Esto significa que la pregunta anterior es sobre cuánto tenía en el pasado antes de que sus padres, tío y tía le dieran dinero.
Por lo tanto, la cantidad de dinero que tenía
= $20 + $5
= $ 25
The total amount I have altogether will be $165
In order to get the total amount that you have, we will add all the cash you were given and the ones you have altogether.
Amount initially owned = $5
Amount given by relatives = $10 + $30 + $100
Amount given by relatives = $140
If he has another $20
Total amount I have = $5 +$140 + $20
Hence the total amount I have altogether will be $165
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Suppose that prices of a certain model of new homes are normally distributed with a mean of $150,000. Find the percentage of buyers who paid:
between $150,000 and $152,400 if the standard deviation is $1200.
Answer:
The percentage is [tex]P(x_1 < X < x_2) = 47.7 \%[/tex]
Step-by-step explanation:
From the question we are told that
The population mean is [tex]\mu = \$ 150000[/tex]
The standard deviation is [tex]\sigma = \$ 1200[/tex]
The prices we are considering is [tex]x_1 = \$150000 \to \ x_2 = \$ 152400[/tex]
Given that the price is normally distributed , the percentage the percentage of buyers who paid between $150,000 and $152,400 is mathematically represented as
[tex]P(x_1 < X < x_2) = P(\frac{x_1 - \mu}{\sigma } < \frac{X - \mu}{\sigma } < \frac{x_2 - \mu}{\sigma })[/tex]
So [tex]\frac{X - \mu}{\sigma }[/tex] is equal to z (the standardized value of X )
So
[tex]P(x_1 < X < x_2) = P(\frac{x_1 - \mu}{\sigma } <Z < \frac{x_2 - \mu}{\sigma })[/tex]
substituting values
[tex]P(x_1 < X < x_2) = P(\frac{150000 - 150000}{1200 } <Z < \frac{152400 - 150000}{1200 })[/tex]
[tex]P(x_1 < X < x_2) = P(0<Z < 2)[/tex]
[tex]P(x_1 < X < x_2) = P( Z < 2) - P( Z < 0 )[/tex]
From the standardized normal distribution table [tex]P(Z < 2 ) = 0.97725[/tex] and
[tex]P(Z < 0) = 0.5[/tex]
So
[tex]P(x_1 < X < x_2) = 0.97725 - 0.5[/tex]
[tex]P(x_1 < X < x_2) = 0.47725[/tex]
The percentage is [tex]P(x_1 < X < x_2) = 47.7 \%[/tex]
It takes an older pump 3 times as long to drain a certain pool as it does a newer pump. Working together, it takes the two pumps 3 hours to
drain the pool. How long will it take the older pump to drain the pool working alone?
Do not do any rounding.
Answer:
it takes approximately 3 hours
Step-by-step explanation:
What is (6b +4) when b is 2?
Answer:
16
Step-by-step explanation:
6*2 = 12
12 + 4 = 16
Write a short statement that expresses a possible function between the given variables. (price of a DVD player, demand f for DVD player)
Answer:
The relation PriceVSDemand usually is an inverse relationship.
This means that, as the price of the object increases, the demand will decrease.
An inverse relationship is:
D = k/P
Where D is the demand, P is the price and K is a constant that depends on the situation.
Of course this relationship also can be something like:
D = k/P^n
With n ≥ 1.
If n = 1 we have the same as above, and if n > 1, the demand decreases faster as the price increases.
If
there are 80 students in class among them 25 are girls and remaining are boys 10 foreigners and remaining are neplese. If 62.5% of them are nepalese boys, what is the probability of selecting foreign girl?
Answer:
1/4
Step-by-step explanation:
There are 80 students.
25 are girls and 55 are boys.
10 are foreigners and 70 are Nepalese.
62.5% are Nepalese boys.
This means that the number of Nepalese boys is:
62.5/100 * 80 = 50
There are 50 nepalese boys and so there are 20 nepalese girls.
The probability of selecting a Nepalese girl is therefore:
20 / 80 = 1/4
Subtracting polynomials
Answer:
-11xy
Step-by-step explanation:
Subtracting a negative means adding.
-14xy - (-3xy) = -14xy + 3xy = -11xy
20x^3+8x^2-30x-12 Rewrite the expression as the product of two binomials.
Answer:
see below
Step-by-step explanation:
20x^3+8x^2-30x-12
Factor out the greatest common factor 2
2 (10x^3+4x^2-15x-6)
Then factor by grouping
2 ( 10x^3+4x^2 -15x-6)
Factor out 2 x^2 from the first group and -3 from the second group
2 ( 2x^2( 5x+2) -3( 5x+2))
Factor out ( 5x+2)
2 ( 5x+2) (2x^2-3)
The 2 can go in either term to get binomials
( 10x +4) (2x^2-3)
or ( 5x+2) ( 4x^2 -6)
Answer:
[tex](10x+4)(2x^2 -3)[/tex]
Step-by-step explanation:
[tex]20x^3+8x^2-30x-12[/tex]
Rewrite expression (grouping them).
[tex]20x^3-30x+8x^2-12[/tex]
Factor the two groups.
[tex]10x(2x^2 -3)+4(2x^2 -3)[/tex]
Take the common factor from both groups.
[tex](10x+4)(2x^2 -3)[/tex]
which is true about the solution to the system of inequalities shown?
A) y ≥ 1/3x + 3 AND 3x - y > 2
B) y ≥ 1/2x + 3 AND 3x - y > 2
C) y ≥ 1/3x + 3 AND 3x + y > 2
D) y ≥ 1/3x + 3 AND 2x - y > 2
Answer:
the solution to the system of inequality is C
Use the interactive number line to find the difference. 4.7 - 2.3 = 4.7 + (-2.3) =
Answer:
Arrow from 0 to 4.7 and from 4.7 to 2.4
Step-by-step explanation:
4.7 is also 0+4.7
arrow from 0 to 4.7.
-2.3 from 4.7 is 4.7-2.3=2.4
arrow from 4.7 to 2.4.
Answer:
Use the interactive number line to find the difference.
4.7 - 2.3 = 4.7 + (-2.3) =
✔ 2.4
Step-by-step explanation:
Find the current I flowing through a square with corners at (0,0,0), (2,0,0), (2,0,2), (0,0,2). The current density is: bold italic J equals bold y with bold hat on top open parentheses y squared plus 5 close parentheses space space space space space open parentheses straight A divided by straight m squared close parentheses
Parameterize the square (call it S) by
[tex]\mathbf s(u,v)=2u\,\mathbf x+2v\,\mathbf z[/tex]
with both [tex]u\in[0,1][/tex] and [tex]v\in[0,1][/tex].
Take the normal vector pointing in the positive y direction to be
[tex]\dfrac{\partial\mathbf s}{\partial v}\times\dfrac{\partial\mathbf s}{\partial u}=4\,\mathbf y[/tex]
Then the current is
[tex]\displaystyle\iint_S(y^2+5)\,\mathbf y\cdot4\,\mathbf y\,\mathrm dA=20\int_0^1\int_0^1\mathrm dA=\boxed{20\,\mathrm A}[/tex]
where [tex]y^2+5[/tex] reduces to just 5 because [tex]y=0[/tex] for all points in S.
Determine the relationship between the measure of angle ADE and the measure of arc AE by circling one of the statements below.
Answer:
The answer c is correct.
Step-by-step explanation:
When two chords share an endpoint, the inscribed angle has half of the measure of the intercepted arc. In this example, ADE is the inscribed angle, so its measure is one half of the arc AE's measure. m<ADE= 1/2(mAE)
i hope this helped :)
The relationship between the measure of angle ADE and the measure of arc AE is m∠ADE = [tex]\frac{1}{2}[/tex] m (arc AE) .
What seems to be the relationship between an inscribed angle and its intercepted arc?The Inscribed Angle Theorem states that the measure of an inscribed angle is half the measure of its intercepted arc. Inscribed angles that intercept the same arc are congruent. This is called the Congruent Inscribed Angles Theorem
According to the question
The relationship between the measure of angle ADE and the measure of arc AE .
∠ADE is a inscribed angle
arc AE is a intercepted arc
According to Inscribed Angle Theorem
∠ADE = [tex]\frac{1}{2}[/tex] arc AE
Hence, the relationship between the measure of angle ADE and the measure of arc AE is m∠ADE = [tex]\frac{1}{2}[/tex] m (arc AE) .
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Find the slope of the line that passes through the points (-2, 4) and (-5, -6).
-217
10/3
-2/3
Answer:
10/3.
Step-by-step explanation:
To find the slope, we do the rise over the run.
In this case, the rise is 4 - (-6) = 4 + 6 = 10.
The run is -2 - (-5) = -2 + 5 = 3.
So, the slope is 10/3.
Hope this helps!
10/3
Step-by-step explanation:
gradient=y²-y¹
x²-x¹
= -6-4
-5-(-2)
= -10
-5+2
= -10
-3
=10/3
What is the formula for the area A of a trapezoid with parallel sides of length B and D, nonparallel sides of length A and C and height H?
A. A = 1/2h (a+c)
B. A = 1/2h (b + d)
C. A = a+b + c + d
D. A= abcd
E. A = 1/2h (a+b+c+d)
Answer:
[tex](B) \dfrac12H (B+D)[/tex]
Step-by-step explanation:
[tex]\text{Area of a trapezoid }= \dfrac12 ($Sum of the parallel sides) \times $Height\\Parallel Sides = B and D\\Height =H\\Therefore:\\\text{Area of the trapezoid }= \dfrac12 (B+D) H[/tex]
The correct option is B.
A loan of $25,475 is taken out at 4.6% interest, compounded annually. If no payments are
made, after about how many years will the amount due reach $37,500? Round to the
nearest year.
Please helpp
Answer:
9 years
Step-by-step explanation:
Find the standard divisor to two decimal places (hundredth) for the given population and number of representative seats.
Population : 140,000
# seats : 9
A) 15,555.56
B) 17,055.56
C) 13,056
D) 14,055.56
E) 16,055
Answer:
A
Step-by-step explanation:
A divisor refers to a number by which another number is to be divided.
So what this question is practically asking us is that which of the values in the options to 2 decimal places is the result dividing the population by the number of seats
Thus we have;
140,000/9 = 15,555.55555 which to 2 decimal places is 15,555.56
The brand name of a certain chain of coffee shops has a 53% recognition rate in the town of Coffeeton. An executive from the company wants to verify the recognition rate as the company is interested in opening a coffee shop in the town. He selects a random sample of 7 Coffeeton residents. Find the probability that exactly 4 of the 7 Coffeeton residents recognize the brand name
Answer:
0.287
Step-by-step explanation:
Use binomial probability:
P = nCr p^r q^(n-r)
where n is the number of trials,
r is the number of successes,
p is the probability of success,
and q is the probability of failure (1-p).
P = ₇C₄ (0.53)⁴ (0.47)³
P ≈ 0.287
g The equation for the change of position of a train starting at x = 0 m is given by The dimensions of b are Select one: a. L-1T-1 b. LT-1 c. T-3 d. LT-2 e. LT-3
Answer:
B. LT⁻¹Step-by-step explanation:
The question is incomplete. Here is the complete question,
The equation for the change of position of a train starting at x = 0 m is given by x =(1/2)at² + bt³. The dimensions of b are__
from the equation of motion given, the constant b is the velocity of the body. For us to get the dimension of b, we have to find the dimension of the velocity .
Since velocity is the rate of change of displacement of a body, then;
VELOCITY = DISPLACEMENT/TIME
displacement is measured in metres while time in seconds.
expressing the formula in terms of its fundamental unit,
v = metre/secs
Since the fundamental quantity of the metre is length (L) and that of seconds is the time (T); the dimensions is expressed as;
V = L/T
V = L * 1/T
V = L * T⁻¹
V = LT⁻¹
Hence the dimension of b is LT⁻¹.
Note that the dimension of a body is written in terms of its fundamental quantities.
The dimensions of b from the given equation are; B: LT⁻¹
Dimensional Analysis
The complete question is;
The equation for the change of position of a train starting at x = 0 m is given by x =(1/2)at² + bt³. The dimensions of b are__
Now, in that equation above, b represents the velocity of the motion. Now, the formula for velocity is;
Velocity = Distance/Time
Now, distance is also called Length and represented by L in basic parameters units while Time is represented by T.
Thus, the dimensions of b are; L/T or expressed as LT⁻¹
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Find the zeros of the quadratic function: y = 6(7x + 9)(8x – 3)
Answer:
hello :- 9/7 and 3/8
Step-by-step explanation:
y = 6(7x + 9)(8x – 3)
y=0 means : 7x+9=0 or 8x-3=0
7x = -9 or 8x=3
x= - 9/7 or x= 3/8
Answer:
-9/7, 3/8
Step-by-step explanation:
The zeroes can be found in the parenthesis.
You need to set each parenthesis to zero first.
7x+9=0
subtract 9
7x=-9
divide 7
x=-9/7
For 8x-3=0
add the 3
8x=3
divide the 8
x=3/8
17. An electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a standard deviation of 40 hours. How large a sample is need it if we wish to be 98% confident that our sample mean will be within 4 hours of the true mean
Answer:
A sample of at least 541 is needed if we wish to be 98% confident that our sample mean will be within 4 hours of the true mean.
Step-by-step explanation:
We are given that an electrical firm manufactures light bulbs that have a length of life that is approximately normally distributed with a standard deviation of 40 hours.
We have to find a sample such that we are 98% confident that our sample mean will be within 4 hours of the true mean.
As we know that the Margin of error formula is given by;
The margin of error = [tex]Z_(_\frac{\alpha}{2}_) \times \frac{\sigma}{\sqrt{n} }[/tex]
where, [tex]\sigma[/tex] = standard deviation = 40 hours
n = sample size
[tex]\alpha[/tex] = level of significance = 1 - 0.98 = 0.02 or 2%
Now, the critical value of z at ([tex]\frac{0.02}{2}[/tex] = 1%) level of significance n the z table is given as 2.3263.
So, the margin of error = [tex]Z_(_\frac{\alpha}{2}_) \times \frac{\sigma}{\sqrt{n} }[/tex]
[tex]4=2.3263 \times \frac{40}{\sqrt{n} }[/tex]
[tex]\sqrt{n}= \frac{40 \times 2.3263}{ 4}[/tex]
[tex]\sqrt{n}=23.26[/tex]
n = [tex]23.26^{2}[/tex] = 541.03 ≈ 541
Hence, a sample of at least 541 is needed if we wish to be 98% confident that our sample mean will be within 4 hours of the true mean.
Use the Pythagorean theorem to find the length of the hypotenuse in the triangle shown below 15 and 39
Answer:
36
Step-by-step explanation:
You did not attach a picture, so I just assumed where the lengths of 15 and 39 were.
50 points + brainliest!
Answer:
( x+2) ^2 = 11
x =1.32,-5.32
Step-by-step explanation:
x^2 + 4x -7 = 0
Add the constant to each side
x^2 + 4x -7+7 = 0+7
x^2 + 4x = 7
Take the coefficient of the x term
4
Divide by 2
4/2 =2
Square it
2^2 = 4
Add this to each side
x^2 + 4x +4 = 7+4
Take the 4/2 as the term inside the parentheses
( x+2) ^2 = 11
Take the square root of each side
sqrt( ( x+2) ^2) =±sqrt( 11)
x+2 = ±sqrt( 11)
Subtract 2 from each side
x = -2 ±sqrt( 11)
To the nearest hundredth
x =1.32
x=-5.32
Answer:
[tex](x+2)^2=11[/tex]
[tex]x=-2 \pm \sqrt{11}[/tex]
Step-by-step explanation:
[tex]x^2+4x-7=0[/tex]
[tex]x^2+4x=7[/tex]
[tex]x^2+4x+4=7+4[/tex]
[tex](x+2)^2=11[/tex]
[tex]x+2=\pm\sqrt{11}[/tex]
[tex]x=-2 \pm \sqrt{11}[/tex]
how many ounces of 7% acid solution and how many ounces of a 23% acid solution must be mixed to obtain 20 oz of a 17% acid solution?
Answer: 7.5 ounces of 7% acid solution is mixed with 12.5 ounces of 23% acid solution to obtain 20 oz of a 17% acid solution.
Step-by-step explanation:
Let x = Ounces of 7% acid solution
y= Ounces of 23% acid solution
According to the question , we have two linear equations:
x+y=20
i.e. y=20-x ...(i)
0.07 x+ 0.23y =0.17 (20)
i.e. 0.07x+0.23y= 3.4 ...(ii)
Substitute value of y from (i) in (ii) , we get
0.07x+0.23(20-x)= 3.4
⇒ 0.07x+4.6-0.23x=3.4 [distributive property]
⇒ 0.07x-0.23x=3.4-4.6 [subtract 4.6 from both sides]
⇒ -0.16x=-1.2
⇒ x = 7.5 [divide both sides by-0.16]
put value of x in (i) , we get y= 20-7.5 =12.5
Hence, 7.5 ounces of 7% acid solution is mixed with 12.5 ounces of 23% acid solution to obtain 20 oz of a 17% acid solution.
Sally can paint a room in 9 hours while it takes Steve 6 hours to paint the same room. How long would it take them to paint the room if they worked together?
Answer:
3.6
Step-by-step explanation:
1/9+1/6
1/3^2+1/2x3=1/x
2+3/3^2x2=1/x
5/3^2x2=1/x
x.5=18
5x=18
5x/5= 18/5
x=18/5
x=3.6
To paint the room if they worked together in 4 hours 14 min.
To find time if they work together.
What is arithmetic?science that deals with the addition, subtraction, multiplication, and division of numbers and properties and manipulation of numbers.An arithmetic sequence is a sequence where the difference between each successive pair of terms is the same. The explicit rule to write the formula for any arithmetic sequence is this:
an = a1 + d (n - 1).
Given that:
(1 room/Sally's time) + (1 room/Steve's time) = (1 room)/(time working together)
1/9+1/6+=+1/x
Multiply both sides by 54x
6x+9x=54
15x=54
x=3.6hours
Working together, they can paint the room in 3 hours 6 min.
So, to paint the room if they worked together in 3 hours 6 min.
Learn more about arithmetic here:
https://brainly.com/question/17114329
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A box contains orange balls and green balls. The number of green balls is seven more than three times the number of orange balls. If there are 67 balls altogether, how many green balls and how many orange balls are there in the box?
Answer:
52 green, 15 orange
Step-by-step explanation:
g + o = 67 g = green, o = orange, x = total
g = 3o + 7
use substitution: (3o + 7) + o = 67
solve for o:
4o + 7 = 67
4o = 60
o = 60/4 = 15
solve for g:
g + 15 = 67
g = 52