leommarcoantonio

leommarcoantonio

26.10.2020 •

Mathematics

Which of the following math statements contain variable(s)? Check all that apply A. 9 - __ = 8 I B. 9-1 = 8
C. 9-1 = x
D. X- = 8

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Ответ:

alysonmariefont

25.08.2021

The solution to the system of equations

x=-2 , y=7

Step-by-step explanation:

Given the system of equations

$\begin{bmatrix}y=3-2x\\ -4x-4y=-20\end{bmatrix}$

$\mathrm{Arrange\:equation\:variables\:for\:elimination}$

$\begin{bmatrix}y+2x=3\\ -4y-4x=-20\end{bmatrix}$

$\mathrm{Multiply\:}y+2x=3\mathrm{\:by\:}4\:\mathrm{:}\:\quad \:4y+8x=12$

$\begin{bmatrix}4y+8x=12\\ -4y-4x=-20\end{bmatrix}$

-4y-4x=-20

$\underline{4y+8x=12}$

4x=-8

so

$\begin{bmatrix}4y+8x=12\\ 4x=-8\end{bmatrix}$

solving for x

4x=-8

Divide both sides by 4

$\frac{4x}{4}=\frac{-8}{4}$

$\frac{4x}{4}=\frac{-8}{4}$

x=-2

$\mathrm{For\:}4y+8x=12\mathrm{\:plug\:in\:}x=-2$

$4y+8\left(-2\right)=12$

4y-16=12

4y=28

Divide both sides by 4

$\frac{4y}{4}=\frac{28}{4}$

y=7

Thus, the solution to the system of equations

x=-2 , y=7

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