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2 years ago

What is the area of the circle of radius 9

Mathematics

2 answers:

fredd [130]2 years ago

7 0

I hope I'm reading this right but the circle has a radius of 9?

a = π r²

81π or 254.34

erma4kov [3.2K]2 years ago

4 0

The equation for the area of a circle is: $\pi r^2$ . Insert 9 as your radius (r) into the equation and solve:
\pi 9^2 = 254.469

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Solve the system of equations:x + 3y - z = -4 2x - y + 2z = 13 3x - 2y - z = -9

tatiyna

Answer:

The solution to the system of equations is

$\begin{gathered} x=\frac{179}{13} \\ \\ y=-\frac{279}{39} \\ \\ z=-\frac{48}{13} \end{gathered}$

Explanation:

Giving the system of equations:

$\begin{gathered} x+3y-z=-4\ldots\ldots\ldots\ldots\ldots\ldots..........\ldots\ldots\ldots\ldots.\ldots\text{.}\mathrm{}(1) \\ 2x-y+2z=13\ldots\ldots...\ldots\ldots\ldots\ldots..\ldots..\ldots\ldots\ldots\ldots\ldots.(2) \\ 3x-2y-z=-9\ldots\ldots\ldots.\ldots\ldots\ldots\ldots....\ldots\ldots.\ldots\ldots\ldots\text{.}\mathrm{}(3) \end{gathered}$

To solve this, we need to first of all eliminate one variable from any two of the equations.

Subtracting (2) from twice of (1), we have:

$5y-4z=-21\ldots\ldots\ldots\ldots\ldots.\ldots.\ldots..\ldots..\ldots\ldots.\ldots..\ldots\text{...}\mathrm{}(4)$

Subtracting (3) from 3 times (1), we have

$3y-5z=-3\ldots\ldots...\ldots\ldots..\ldots\ldots\ldots\ldots\ldots.\ldots\ldots\ldots\ldots\ldots..\ldots\ldots(5)$

From (4) and (5), we can solve for y and z.

Subtract 5 times (5) from 3 times (4)

$\begin{gathered} 13z=-48 \\ \\ z=-\frac{48}{13} \end{gathered}$

Using the value of z obtained in (5), we have

$\begin{gathered} 3y-5(-\frac{48}{13})=-3 \\ \\ 3y+\frac{240}{13}=-3 \\ \\ 3y=-3-\frac{240}{13} \\ \\ 3y=-\frac{279}{13} \\ \\ y=-\frac{279}{39} \end{gathered}$

Using the values obtained for y and z in (1), we have

$\begin{gathered} x+3(-\frac{279}{39})-(-\frac{48}{13})=-4 \\ \\ x-\frac{279}{13}+\frac{48}{13}=-4 \\ \\ x-\frac{231}{13}=-4 \\ \\ x=-4+\frac{231}{13} \\ \\ x=\frac{179}{13} \end{gathered}$

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8 months ago

Find the slope of a line perpendicular to 2x-y-16

Alekssandra [29.7K]

put the equation 2x - y = 16 in the form of y = mx + c

2x - y = 16

2x = 16 + y

y = 2x - 16

the slope of this line is 2. the slope of a line perpendicular to it would be the negative reciprocal of 2. in other words, it would multiply with 2 to give -1.

you can form this equation with that info

2x = -1

x = -1/2

you can flip and change the sign (numerator) of 2/1

2/1

= -1/2

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2 years ago

If f(x)=3x^2+1 and g(x) =1-x, what is the truly value of (f-g)(2)

Lilit [14]

Answer:

Step-by-step explanation:

f(x)=3x²+1

f(2) = 3 x 2² + 1 = 13

g(x) =1-x

g(2) = 1 - 2 = -1

(f-g)(2) f(2) - g(2) = 13 - (-1) = 14

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2 years ago

Help please!! Don’t understand! 6th grade math

Agata [3.3K]

Answer:

4. is 6.6

Step-by-step explanation:

I hope this helps

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2 years ago

Please solve this for me please

Natalka [10]

I’m having trouble reading your equations is it
(2i-1/x+1)^(4)-13(x-1/x+1)^(2)+36=0
I just want to confirm before doing it just comment if that’s the correct equation.

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2 years ago