Explain why 21i^2 is equivalent to -21

Answers

Answer 1

Answer:

Step-by-step explanation:

The imaginary number 'i' is equal to the square root of -1. If you were to square the square root, they both cancel and you get -1.

[tex]21i^2=21(\sqrt{-1} )^2=21(-1)=-21[/tex]


Related Questions

Rectangular prism is 7 feet wide and 3 feet high. Its volume is 189 cubic feet. What is the length of the rectangular prism?

Answers

The length is 9 feet.
The formula for Area is A= L*W*H.
You are given A=189, W= 7 feet and H= 3 feet. Solve formula for
L.
189= L*7* 3
189=21 L
Divide both sides by 21 to solve for L
189/21 = 21L/21
9=L

⚠ 25 POINTS AND BRAINLIESTTT ⚠

Lee and Tom are visiting Disney World. They decide to take a taxi from their hotel to the park. Yellow Taxi charges a $2.00 pickup fee and $0.35 per mile. Checker Cab charges a $1.75 pick up fee and $0.40 per mile. Determine for what number of miles the two companies would charge the same amount of money.

Answers

Answer:

Your answer is

$5 after 3.75 miles

Hope that this is helpful. Tap the crown button, Like & Follow me

Answer:

5$ after 3.75 miles

Hope this helps!  :)

Step-by-step explanation:

Please help me answer this question of Fractional Linear Equations. I provided the example of how to do it in case you forgot/don't know how to anymore. I'll give out brainliest. Thank youu

Answers

15 = ½ (7x-6)

distribute ½ into parentheses

15 = ½(7x) - ½(6)

15 = ⁷/₂x - 3

multiply by 2

30 = 7x -6
subtract +6 to both side

30 + 6 = 7x

36 = 7x

devide 7 to both side

36
------ = x
7

its easy please ill give brainiest dont guess

Answers

Answer:

I don't know

Step-by-step explanation:

acute triangle has 2 right angles / 3 acute angles

obtuse triangles has 0 right angles / 2 acute angles

right triangle has 1 right angle / 2 acute angles

A chemical compound requires 8 ounces of chemical A and 12 ounces of chemical B. A mixture contains 24 ounces of chemical A and 30 ounces of chemical B. How can you fix the mixture to make the chemical compound?

Answers

Add 6oz of chemical B and remove 1/3 of the total mixture.
I might always be wrong.
Explanation:
Since 8x3=24 and since 12x3=36 you need to add 6oz of chemical B to have 24oz of chemical A and 36oz of chemical B.
Take 1/3 of the total mixture to have 8oz of chemical A and 12oz of chemical B.

Please show work. Cant even explain how much i hate mathematics

Answers

no pic?????????????????????????

Answer:

there is no attachment

Step-by-step explanation:

find the difference 16.7-3.24​

Answers

Answer: 13.46

Step-by-step explanation:

Subtract and you will get 13.46

Answer: 13.46

Step-by-step explanation:

Find the value of x.

Answers

Answer:

         x = 6

Step-by-step explanation:

[tex]\dfrac{6x-1}{10x+5}=\dfrac{42}{78}\\\\\\\dfrac{6x-1}{10x+5}=\dfrac{7}{13}\\\\\\13(6x-1)=7(10x+5)\\\\78x-13=70x +35\\\\78x-70x=35+13\\\\8x=48\\\\x=6[/tex]

Order the values from least to greatest

6/17 0.36 3.6%

Answers

Answer:

3.6%, 6/17, 0.36

Step-by-step explanation:

Convert to decimal:

6/17 ≈ 0.3529

0.36 = 0.36

3.6% 3.6/100 = 0.036

Order:

0.036, 0.3529, 0.36

Hope this helps.

Which of the following systems of equations has a solution in which the x-value is greater than the y-value?

Answers

Answer:

a

Step-by-step explanation:

Answer:

a

Step-by-step explanation:

5x-2y=12....... .....

Four less than three times a number n. Write an algebraic expression.

Answers

Answer:

3n - 4

Step-by-step explanation:

Answer:

3n - 4

Three times a number n = 3n and you just subtract 4 from that!

The students in Mr. Lin's class are having a car wash to raise money for a trip. They need at least
$600 to go on the trip. They have already raised $61. They make $14 for every car they wash.
The students want to know how many cars they need to wash to go on the trip.

Let c be the number of
cars the students wash. Write an inequality that represents the situation.

Answers

Answer:

14c + 61 is greater than or equal to (put the greater than symbol with the line underneath there) 600

The inequality for raising the money will be written as 14c + 61 > 600.

What is inequality?

When two expressions are connected by a sign like "not equal to," "greater than," or "less than," it is said to be inequitable. The inequality shows the greater than and less than the relation between variables and the numbers.

Given that the students in Mr. Lin's class are having a car wash to raise money for a trip. They need at least $600 to go on the trip. They have already raised $61. They make $14 for every car they wash.

The inequality will be written as,

14c + 60 > 600

Here, c is the number of the car wash.

To know more about inequality follow

https://brainly.com/question/24372553

#SPJ2

I need help friends! Pls, help me I will review it once you answered :)

Answers

No, it is not a possible solution because 4$ x 4h= 16 and then 12h x 8$ = 96. Together it makes 112$ but the goal is 120$, therefore it is a incorrect possible solution.

Could u help me out with this question? It involves SIN COS TAN (SOH CAH TOA)

Answers

It’s CAH I have hegarty maths I hate it do cos to the power of -1

Please I need help !!!

Answers

I think it would be 15 meters per second to the east.

78m divided by 5.2 seconds would be 15 meters per second.

In Triangle FGH, f = 65 inches, g = 48 inches and h=70 inches. Find the measure of Angle G to
the nearest degree.
Submit Answer
Answer:

Answers

Answer:41

Step-by-step explanation:

Given m||n fine the value of x

Answers

x is going to equal 33

In a lab, 700 cells are present at the beginning of an experiment. During the first 7 hours,
the number of cells increased by 12% each hour.
Estimate the time when the number of cells is 1735.
Round answer to nearest whole hour.

Answers

Answer:

2 hours

Step-by-step explanation:

1=700

x=1735

1735=700x

1735/700

x=2.47

Answer:

Step-by-step explanation:

This is an exponential equation of the form, A=ar^t, where a is the initial amount and r is the common ratio or rate of growth and t is time. In this case.

A=700(1.12)^t and we want to find when A=1735

1735=700(1.12)^t

1735/700=1.12^t

ln(1735/700)=t(ln(1.12))

t=(ln(1735/700))/(ln(1.12))

t=8 hours

Sole the equation x^2=16

Answers

Answer:

4

Step-by-step explanation:

4^2 = 4x4 = 16

Answer:

x = ± 4

Step-by-step explanation:

Given

x² = 16 ( take the square root of both sides )

x = ± [tex]\sqrt{16}[/tex] = ± 4

That is x = - 4, x = 4

x + 5 < 13 my teacher

Answers

Answer:

x ≤ 8

Step-by-step explanation:

x + 5 ≤ 13

subtract 5 from both sides

x ≤ 8

HELP NEEDED BRAINLIEST AND 5 STAR Is it posible to make a triangle with 3 feet, 8 feet, and 4 feet. Explain why or why not plzzzzzz.z

Answers

Answer:

No, IMPOSSIABLE

Step-by-step explanation:

According to the first triangle inequality theorem, the lengths of any two sides of a triangle must add up to more than the length of the third side. In you case 3+4=7.  7 is less than 8.

Doña Catalina tiene un terreno de una hectárea. Si desea dividir el terreno en parcelas de 400 m2, ¿cuántas parcelas obtendrá?

Answers

Answer: guyguyguyguyuguyguyg

Step-by-step explanation:

At a restaurant the bill came to $62.00. If you leave $69.44, what percent tip is
that?

help me please :0000

Answers

The answer would be 12%

Answer:

12%

Step-by-step explanation:

Take 69.44 and subtract 62.

You should get 7.44.

If you take the original 62 & multiply by .12, you get the 7.44 tip.

Ben is 12 years older than Ishaan. Ben and Ishaan first met two years ago. Three years ago, Ben was 4 times as
old as Ishaan.
How old is Ishaan now?

Answers

Ishaan is now 7 years old
4 years old
hope this helped

How do solve for x in supplementary ,complementary and vertical angles

Answers

U do supplementary + complementary
Supplementary plus complementary

A rectangular garden has an area of 60 squared feet. The garden is 4 feet longer than it is wide. Which equation can be used to determine the length and width of the garden?

Answers

Answer: See explanation

Step-by-step explanation:

Let the width be x

Then, the length will be x+4

Area = Length × Width

Therefore,

x × (x+4) = 60

x² + 4x = 60

x² + 4x - 60 = 0

x² + 10x - 6x - 60 = 0

x(x + 10) - 6(x + 10) = 0

(x - 6)(x + 10) = 0

x - 6 = 0

x = 6

The width is 6feet

Length = 6+4 = 10 feet

Factor the following: 7k^2+3k-10

Answers

Step-by-step explanation:

7k² + 3k - 10

= 7k² + ( 10 - 7 ) k - 10

= 7k² + 10k - 7k - 10

= k( 7k + 10 ) - 1( 7k + 10)

= ( 7k + 10) ( k - 1)

Hope it will help :)

Answer:

Step-by-step explanation:

Use the Pythagorean Theorem to determine the roots

k = 1,-10/7

7k^2+3k-10 = 7(k-1)(k+10/7) = (k-1)(7k+10)

For each situation, write an expression in simplest form that represents the
total amount.

On Monday, Rana spent d dirhams on lunch. She spent AED 0.50 more on Tuesday than
on Monday. On Wednesday, she spent twice as much as she did on Tuesday.

3d +1
40+ 1.5
3d


Plz helpp

Answers

Ummmmmmmmmm 3D I think

f(x) = x2 + 1
What is f(f(x))?
O A+ 2x2+1
A+ 2x2+2
O A +2
O A+1

Answers

Answer:

Your answer is x^4 + 2 x^2 +2

Hope that this is helpful. Vote and like it

prove that 151^3-25^3 is divisible by 126

Answers

Start off by doing 151^3= 3442951
Then do 25^3= 15625
Subtract them= 3442951-15625= 3427326
Than divide the answer 3427326 by 126
3427326 divided by 126= 27201
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