What is the value of x plz help

Answer:

6x

Step-by-step explanation:

7x - x

Factor out x

x( 7-1)

6x

Answer:

6x

Step-by-step explanation:

7x - x

Apply rule : a = 1a

x = 1x

7x - 1x

Factor out x.

(7 - 1)x

(6)x

Answer:

The correct option is C

Step-by-step explanation:

From the question we are told that

   The  sample mean is  [tex]\= x =[/tex]$21.51

    The 95%  confidence level interval  is  [$ 20.52 , $22.48]

Generally the 95%  confidence level interval is mathematically represented as

      [tex]\= x - MOE < \mu < \= x + MOE[/tex]

Where  MOE  is the margin of error which defines in percentage the amount by which the sample mean taxi fare(for the 7 taxi  ) will differ from the average taxi fare between Logan Airport and downtown Boston will fall between

Also  [tex]\mu[/tex] is the  average taxi fare between Logan Airport and downtown Boston

So we see that the this 95%  confidence level interval tells us  that  the average taxi fare between Logan Airport and downtown Boston will fall between $20.52 and $22.48.

Answer:

0.0668 or 6.68%

Step-by-step explanation:

Variance (V) = 10,000

Standard deviation (σ) = √V= 100

Mean score (μ) = 500

The z-score for any test score X is:

[tex]z=\frac{X-\mu}{\sigma}[/tex]

For X = 650:

[tex]z=\frac{650-500}{100}\\z=1.5[/tex]

A z-score of 1.5 is equivalent to the 93.32nd percentile of a normal distribution. Therefore, the probability that he or she will make a score of 650 or more is:

[tex]P(X\geq 650)=1-P(X\leq 650)\\P(X\geq 650)=1-0.9332\\P(X\geq 650)=0.0668=6.68\%[/tex]

The probability is 0.0668 or 6.68%

The probability that he or she will make a score of 650 or more is 0.0668.

Let X = Scores made on a certain aptitude test by nursing students

X follows normal distribution with mean = 500 and variance of 10,000.

So, standard deviation = [tex]\sqrt{10000}=100[/tex].

z score of 650 is = [tex]\frac{\left(650-500\right)}{100}=1.5[/tex].

The probability that he or she will make a score of 650 or more is:

[tex]P(X\geq 650)\\=P(z\geq 1.5)\\=1-P(z<1.5)\\=1-0.9332\\=0.0668[/tex]

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The complete part of the first sentence is;

A manufacturer claims that the average tensile strength of thread A exceeds the average tensile strength of thread B by at least 12 kilograms.

Answer:

we fail to reject the null hypothesis and conclude that the difference of the average tensile strength of thread A and thread B is less than 12

Step-by-step explanation:

We are given;

n_A = 16

n_B = 16

x'_A = 185 kg

x'_B = 178 kg

s_A = 6 kg

s_B = 9 kg

Let μ_A denote the population average tensile strength of thread A

Also, Let μ_B represent the population average tensile strength of thread B

Thus;

Null Hypothesis; H0;μ_A - μ_B ≤ 12

Alternative hypothesis;H1; μ_A - μ_B > 12

From the image attached, with a significance level of 0.05, the critical value for right tailed is 1.645. So we will reject the hypothesis is z > 1.645

Formula for z is;

z = (x'_A - x'_B - d_o)/√((s_A²/n_A) + (s_B²/n_B))

Plugging in the relevant values, we have;

z = (185 - 178 - 12)/√((6²/16) + (9²/16))

z = -5/2.7041634566

z = - 1.849

Since the z-value is less than 1.645,we fail to reject the null hypothesis and conclude that the difference of the average tensile strength of thread A and thread B is less than 12

Answer:

Im not 100% sure, but I think it is:

No

No

No

Yes

Answer:

The 99 % confidence interval on the basis of mean is ( 21.7393  ;   22.0257)

Step-by-step explanation:

Mean = Sum of observations / Number of observations

Mean = 21.88 +21.76 +22.14 +21.63+ 21.81 +22.12+ 21.97+ 21.57+ 21.75+ 21.96 +22.20 +21.80/ 12

Mean =x`= 262.59/12=  21.8825

Standard Deviation = s= ∑x²/n - ( ∑x/n)²

∑x²/n= 478.7344 +473.4976 + 490.1796+467.8569+ 475.6761 + 489.2944+ 482.6809+ 465.2649+ 473.0625+ 482.2416 +492.84 + 475.24/ 12

∑x²/n= 5746.5689/12= 478.8807 = 478.881

Standard Deviation = s= ∑x²/n - ( ∑x/n)²

s= 478.881- (21.8825)²= 478.881-478.843= 0.037

The confidence limit 99% for the mean will be determined by

x` ± α(100-1) √s/n

Putting the values in the above equation

= 21.8825 ± 2.58 √0.037/12

Solving the square root

= 21.8825 ± 2.58 (0.05549)

Multiplying the square root with 2.58

=21.8825 ± 0.1432

Adding and subtracting would give

21.7393  ;   22.0257,

Hence the 99 % confidence interval on the basis of mean is ( 21.7393  ;   22.0257)

Answer:

y < -12

Step-by-step explanation:

Step 1: Subtract 15 on both sides

y + 15 - 15 < 3 - 15

y < -12

This inequality means the any number smaller than -12 would work. So:

-123415235 would work

-1234 would work

-46527 would work

2 would NOT work

6 would NOT work

Answer:

Step-by-step explanation:

[tex]y + 15 < 3[/tex]

Move constant to RHS and change its sign:

[tex]y < 3 - 15[/tex]

Calculate the difference

[tex]y < - 12[/tex]

Hope this helps..

Good luck on your assignment..

Answer:

The most appropriate  value of the critical value is 2.289.

Step-by-step explanation:

We are given that a researcher takes a random sample of 41 bulbs and determines  that the mean consumption is 1.3 watts per hour with a standard deviation of 0.7.

We have to find that when constructing a 97% confidence interval, which would be the most appropriate  value of the critical value.

Firstly, as we know that the test statistics that would be used here is t-test statistics because we don't know about the population standard deviation.

So, for finding the critical value we will look for t table at (41 - 1 = 40) degrees of freedom at the level of significance will be [tex]\frac{1 - 0.97}{2} = 0.015[/tex] .

Now, as we can see that in the t table the critical values for P = 1.5% are not given, so we will interpolate between P = 2.5% and P = 1%, i.e;

     [tex]\frac{0.015 - 0.025}{0.025-0.01}= \frac{\text{Critcal value}-2.021}{2.021-2.423}[/tex]

So, the critical value at a 1.5% significance level is 2.289.

Answer:

answer D

Step-by-step explanation:

Lets have a look to the graph and to the  each of given functions.

As we can see in graph it intersects X in points (-3;0) and (-6;0) that means the function has the roots x1=-3 and x2=-6

Function A  has the roots x1=+3 and x2=+6 => doesn' t fit

Function B has only 1 root x=2 , so can be factorized y=(x-2)^2 => doesn' t fit

Function C has 2 roots  x1=4  and x2=-5 => doesn' t fit

Function D can be factotized as y=(x+6)*(x+3) so has 2 roots x1=-6 x2=-3 => exactly what we need!!!

We can also notice that the coefficient near x²  is equal to 1  and is positive.

That means the legs of the graph directed up,- this is exactly like in our graph. It gives us extra argument why we choose D.

Answer:

c = 11.3 mi/h

Step-by-step explanation:

Since Square has all of the same sides, hence bobs speed will be the same for all of the sides.

All of the sides are equal in a square

=> Let's consider the two sides along with the diagonal a right angled triangle

=> [tex]c^2 = a^2 + b^2[/tex]

Where c is the speed of Rob along the diagonal and b and c is the speed of Bob along the side

=> [tex]c^2 = 8^2+8^2[/tex]

=> [tex]c^2 = 64+64[/tex]

=> [tex]c^2 = 128\\[/tex]

Taking sq root on both sides

=> c = 11.3 mi/h

Answer:

hundreths

Step-by-step explanation:

After the decimal there is tenths, hundreths thousandnths, tens of thousands e.t.c

Answer:

Hello! The answer will be hundredths.

Step-by-step explanation:

The 5 means the thousandths.

The 0 means the hundredths.

The 8 means the tenths.

The 7 means the ones

And the 6 means the tens.

Hope this helps! :)

( below I attached a picture, which might be helpful.)

Answer:

Step-by-step explanation:

Using the following data:

H0:p=0.40 (null hypothesis)

Ha:p>0.40 (alternative hypothesis)

The p-value was determined to be 0.001.

a significance level of 5%

Since the p value (0.001) is less than the significance level (0.05), we will reject the null hypothesis and then we would conclude that the proportion of students that are nursing majors is greater than 0.4.

Answer:

p value= 0.131

Step-by-step explanation:

Since we have calculated the test statistic, we can now proceed to find the p-value for this hypothesis test.Using the test statistic and since the hypothesis test is a left tailed test, the p-value will then be the area under the standard normal curve to the left of the test statistic of -1.12.Using the Standard Normal table given above, the area under the standard normal curve to the left of the test statistic of -1.12 is 0.131 (rounded to 3 decimal places.Thus the p-value = 0.131.

Step-by-step explanation:

Formula for compound interest is given by

[tex]A = P(1 + R) ^{n} [/tex]

Where

A is the amount at the end of the period

P is the principal

R is the rate

n is the period

The interest = A - P

From the question

P = $ 3200

n = 3 years

R = 40%

So we have

[tex]A = 3200 \times 2.744[/tex]

A = $ 8780.80

The interest is

$ 8780.80 - $3200

Hope this helps you

Answer:

O A. 20.78 units

Step-by-step explanation:

APEXX

Answer:  Focus = (-2, 3)

Step-by-step explanation:

[tex]y=-\dfrac{1}{4}x^2-x+3\\\\\rightarrow a=-\dfrac{1}{4},\ b=-1[/tex]

First let's find the vertex. We do that by finding the Axis-Of-Symmetry:

[tex]AOS: x=\dfrac{-b}{2a}\quad =\dfrac{-(-1)}{2(\frac{-1}{4})}=\dfrac{1}{-\frac{1}{2}}=-2[/tex]

Then finding the maximum by inputting x = -2 into the given equation:

[tex]y=-\dfrac{1}{4}(-2)^2-(-2)+3\\\\y=-1+2+3\\\\y=4[/tex]

The vertex is: (-2, 4)

Now let's find p, which is the distance from the vertex to the focus:

[tex]a=\dfrac{1}{4p}\\\\\\-\dfrac{1}{4}=\dfrac{1}{4p}\\\\\\p=-1[/tex]

The vertex is (-2, 4) and p = -1

The focus is (-2, 4 + p) = (-2, 4 - 1) = (-2, 3)

Answer:

Hey there!

The line can be expressed into y intercept form, y=3x+1.

Thus, in y=mx+b form, m is the slope, and we see that 3 is the slope of the line.

Let me know if this helps :)

Answer:

Step-by-step explanation:

B. ​No, two events with nonzero probabilities cannot be independent and mutually exclusive because if two events are mutually​ exclusive, then when one of them​ occurs, the probability of the other must be zero.

For two mutually exclusive events , with non- zero probabilities , when one occurs , the other can not happen . In this way they become dependent events . In this way , for two events to be both independent and mutually exclusive , at least one of the two events must have zero probability .

It should be noted that two events with nonzero probabilities cannot be independent and mutually exclusive because if two events are mutually​ exclusive, then when one of them​ occurs, the probability of the other must be zero.

Mutually exclusive events simply means the events that cannot take place at the same time. The occurrence of one of the events will prevent the other event from occuring.

Therefore, two events with nonzero probabilities cannot be independent and mutually exclusive because if two events are mutually​ exclusive, then when one of them​ occurs, the probability of the other must be zero.

Read related link on:

https://brainly.com/question/15179003

Answer:

b, c, e

Step-by-step explanation:

the reasons have to include an angle from both of the parallel lines. by using process of elimination it is b, c, e. I also got it right

Answer:

B. a=d

C. c=d

E. b + d=180°

Step-by-step explanation:

Got Correct On MyPath.

Answer:

z < 4

Step-by-step explanation:

2(3z-4) < 16

Divide by 2 on both sides

3z-4 < 8

Add 4 to both sides

3z < 12

Divide by 3 on both sides

z < 4

Answer:

  (T, C, J) = (in dollars)

     (10000, 10000, 0),

     (15000, 4915.97, 84.03),

     (18181.82, 1680.67, 137.51)

Step-by-step explanation:

There are a number of ways to approach this question. We have chosen an approach that determines the investments required to achieve interest rate targets.

__

For an overall interest rate of I, the proportion that must be invested at rate I1 < I < I2 is ...

  proportion at I1 = (I2 -I)/(I2 -I1)

Similarly, the proportion that must be invested at I2 is what's left over. It can be computed similarly:

  proportion at I2 = (I -I1)/(I2 -I1)

__

We want an overall interest rate of $2000/$20000 = 10%.

Given available interest rates of 9%, 11%, and 130%, we need to have investments at a rate lower than 10% and at a rate higher than 10%.

If we use only the options for 9% and 11% (no junk bonds), then we can compute ...

  proportion at 9% = (11 -10)/(11 -9) = 1/2

  proportion at 11% = (10 -9)/(11 -9) = 1/2

1st Option:

  $10,000 in treasury bills; $10,000 in corporate bonds

__

Suppose we want to achieve a 13% return on our investments at 11% and 130%. Then the proportion invested at 9% will use this value for I2:

  proportion at 9% = (13 -10)/(13 -9) = 3/4

Of the remaining 1/4 of the money, we can achieve a 13% return by mixing the investments like this:

  proportion at 11% = (130 -13)/(130 -11) = 117/119

  proportion at 130% = (13 -11)/(130 -11) = 2/119

2nd option:

  $20,000 × 3/4 = $15,000 in treasury bills

  $5000 × 117/119 = $4,915.97 in corporate bonds

  The remaining amount, $84.03 in junk bonds

__

Let's suppose we want a 20% return on our investment in junk bonds and corporate bonds. Then the proportion of the money invested at 9% will be ...

  proportion at 9% = (20 -10)/(20 -9) = 10/11

And the proportion at 11% will be ...

  proportion at 11% = (130 -20)/(130 -11) = 110/119 . . . (of the remaining 1/11 of the funds)

3rd option:

  $20,000 × 10/11 = $18,181.82 in treasury bills

  $1,818.18 × 110/119 = $1,680.67 in corporate bonds

  The remaining amount, $137.51 in junk bonds

_____

Additional comment

The most that could be invested in Junk Bonds is $165.29. If the remainder is invested in Treasury Bills, then the overall return will be $2000. (You could consider this to be a 4th option.)

Answer:

Step-by-step explanation:

First, note this parameters from the question.

We let x = number of $5 increases and number of 10 decreases in plates sold.

Our Revenue equation is:

R(x) = (300-10x)(10+5x)

We expand the above equation into a quadratic equation by multiplying each bracket:

R(x) = 3000 + 1500x - 3000x - 1500x^2

R(x) = -1500x^2 - 1500x + 3000 (collect like terms)

Next we simplify, by dividing through by -1500

= 1500x^2/1500 - 1500x/1500 + 3000/1500

= X^2 - x + 2

X^2 - x + 2 = 0

Next, we find the axis of symmetry using the formula x = -b/(2*a) where b = 1, a = 1

X = - (-1)/2*1

X = 1/2

Number of $5 increases = $5x1/2 = $2.5

=$2.5 + $20 = $22.5 ticket price gives max revenue.

Answer:

The regression model is:

y = 20.29 + 0.73·x

Step-by-step explanation:

In this case a regression model is to be formed to predict the final average in the course based on the first test grade.

Use Excel to form the regression model.

The output is attached below.

The regression model is:

y = 20.29 + 0.73·x

Predict the final average of a students who made an 83 on the first test as follows:

y = 20.29 + 0.73·x

  = 20.29 + 0.73 × 83

  = 80.88

The final average of a students who made an 83 on the first test would be 80.88.

From the output:

R² = 0.839

Then the correlation coefficient will be:

[tex]r=\sqrt{R^{2}}=\sqrt{0.839}=0.91597\approx 0.92[/tex]

The value of r is 0.92.

The coefficient of determination R² specifies the percentage of the variance in the dependent-variable (Y) that is forecasted or explained by linear regression and the forecaster variable (X, also recognized as the independent-variable).

In this case, the R² value of 0.839 implies that 83.9% of the variation in the final average can be explained by the grades in the first test.

Answer:

13

Step-by-step explanation:

The range of a set of data is the difference between the highest and lowest values in the set.

So, in order to find the range, you first order the data from least to greatest. Which it is already.

3, 7, 11, 14, 16

Then subtract the smallest value from the largest value in the set.

16 - 3 = 13

Hope this helps you out! : )

Answer:

The probability that the sample mean of IQ scores will not differ from the population mean by more than 2 points is 0.67

Step-by-step explanation:

Please check attachment for complete solution and step by step explanation

Answer:

x = -15 + y

Step-by-step explanation:

Let next days temperature be x and the temperature rise be y

=> x = -15 + y

The next day's temperature will be more since it "rose".

Answer:

[tex]\boxed{x=-15+y}[/tex]

Step-by-step explanation:

Let the temperature on Feb 10, 1934 be x.

Let the temperature increase be y.

On Feb 9, the temperature was -15F.

On Feb 10, the temperature increased.

[tex]x=-15+y[/tex]

Answer:

The cost of printing 142 more posters when 18 has already been printed is $5.57.

Step-by-step explanation:

We are given that the marginal cost (dollars) of printing a poster when x posters have been printed is given by the following equation C'(x)=x^-3/4.

The given equation is: [tex]C'(x) = x^{\frac{-3}{4} }[/tex]

The cost of printing 142 more posters when 18 have already been printed is given by;

Integrating both sides of the equation and using the limits we get;

[tex]\int_{a}^{b} C'(x) dx=\int_{18}^{142} x^{\frac{-3}{4}}dx[/tex]

As we know that  [tex]\int\limits {x}^{n} \, dx = \frac{x^{n+1} }{n+1}[/tex] , so;

          =  [tex]\frac{x^{\frac{-3}{4}+1 } }{\frac{-3}{4}+1 } ]^{142} __1_8[/tex]

          =  [tex]\frac{x^{\frac{1}{4} } }{\frac{1}{4} } ]^{142} __1_8[/tex]

          =  [tex]4[x^{\frac{1}{4} } } ]^{142} __1_8[/tex]

          =  [tex]4[(142)^{\frac{1}{4} }- (18)^{\frac{1}{4} }} ][/tex]

          =  $5.57

Hence, the cost of printing 142 more posters when 18 has already been printed is $5.57.

Answer:

D. The statement is false. Double blinding is used to decrease the placebo effect.

Step-by-step explanation:

In a double blind study, neither researchers nor the participants know which group is receiving the placebo. If the researchers do not know which group took the medication, they cannot influence the behavior of this group, knowingly or nor, by suggesting how they should behave.

Therefore, a​ double-blind experiment is used to decrease the placebo effect.

Answer:

Step-by-step explanation:

  D=4300x /x² + 40.

x = 1

D = 4300 / 41 = 104.88 p / mi²

x = 6

D = 25800 / 76

= 339.47  p / mi²

Population density increases as we go away from city's centre .

b )

x = 10

D=4300x /x² + 40.

D = 307.14 p/ mi²

x = 30

D = 137.23 p / mi²

Population decreases .

c )

when x is very high , density will decrease due to squared denominator whose value increases very fast .

d )

D < 200

4300x /x² + 40 < 200

4300 x < 200 x² + 8000

43 x < 2 x² + 80

2 x² - 43 x + 80 > 0

( x - 19.44 ) ( x - 2.05 ) > 0

Range x <  2.05

x > 19.44

Answer:

The z-score is  [tex]z = 2.65[/tex]

The length of days is not unusual

Step-by-step explanation:

From the question we are told that

     The population mean is  [tex]\mu = 267.6 \ days[/tex]

     The standard deviation is  [tex]\sigma = 15.4 \ days[/tex]

      The value considered is  [tex]x = 309 \ days[/tex]

The z-score is mathematically represented as

           [tex]z = \frac{x - \mu}{\sigma }[/tex]

            [tex]z = \frac{309 - 267.6}{15.6 }[/tex]

           [tex]z = 2.65[/tex]

Now given that the z-score is not greater than 3  then we can say that the length of days is not unusual

(reference khan academy)

Answer:

1.    [tex]\alpha = 79[/tex] and [tex]\beta = 19[/tex]

2.   [tex]cos(60)[/tex]

3.   [tex]cos(60) = \frac{1}{2}[/tex]

Step-by-step explanation:

Given

[tex]cos(\alpha - \beta )[/tex]

[tex]cos(79)cos(19) + sin(79)sin(19)[/tex]

Solving for [tex]\alpha[/tex] and [tex]\beta[/tex]

In trigonometry;

[tex]cos(\alpha - \beta ) = cos\alpha\ cos\beta + sin\alpha\ sin\beta[/tex]

Equate the above expression to [tex]cos(79)cos(19) + sin(79)sin(19)[/tex]

[tex]cos(\alpha - \beta ) = cos\alpha\ cos\beta + sin\alpha\ sin\beta[/tex] and [tex]cos(\alpha - \beta ) = cos(79)cos(19) + sin(79)sin(19)[/tex]

By comparison

[tex]cos\alpha\ cos\beta + sin\alpha\ sin\beta = cos(79)cos(19) + sin(79)sin(19)[/tex]

Compare expression on the right hand side to the left hand side

[tex]cos\alpha\ cos\beta = cos(79)cos(19) \\\\ sin\alpha\ sin\beta = sin(79)sin(19)[/tex]

This implies that

[tex]cos\alpha\ = cos(79)\\cos\beta = cos(19) \\\\ and\\\\sin\alpha\ = sin(79)\\sin\beta = sin(19)[/tex]

By further comparison

[tex]\alpha = 79[/tex] and [tex]\beta = 19[/tex]

Substitute [tex]\alpha = 79[/tex] and [tex]\beta = 19[/tex] in [tex]cos(\alpha - \beta )[/tex]

[tex]cos(\alpha - \beta ) = cos(79 - 19)[/tex]

[tex]cos(\alpha - \beta ) = cos(60)[/tex]

Hence, the expression is [tex]cos(60)[/tex]

Solving for the exact values;

Express [tex]cos(60)[/tex] as a difference of angles

[tex]cos(60) = cos(90 - 30)[/tex]

Recall that [tex]cos(\alpha - \beta ) = cos\alpha\ cos\beta + sin\alpha\ sin\beta[/tex]

So;

[tex]cos(90- 30 ) = cos(90) cos(30) + sin(90) sin(30)[/tex]

------------------------------------------------------------------------------------

In trigonometry;

[tex]cos(90) = 0[/tex]; [tex]cos(30) = \frac{\sqrt{3}}{{2}}[/tex]; [tex]sin(90) = 1[/tex]; [tex]sin(30) = \frac{1}{2}[/tex];

---------------------------------------------------------------------------

[tex]cos(90- 30 ) = cos(90) cos(30) + sin(90) sin(30)[/tex] becomes

[tex]cos(90- 30 ) = 0 * \frac{\sqrt{3}}{2} + 1 * \frac{1}{2}[/tex]

[tex]cos(90- 30 ) = 0 + \frac{1}{2}[/tex]

[tex]cos(90- 30 ) = \frac{1}{2}[/tex]

Hence;

[tex]cos(60) = \frac{1}{2}[/tex]