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Solve for the value of x and y by elimination.x − y = 12x + 2y = 21

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\begin{gathered} x-y=12 \\ x+2y=21 \end{gathered}

Let's solve for the value of x and y by elimination.

1. First, eliminate the variable "x" by subtracting the two equations.


(x-y)-(x+2y)=12-21
x-y-x-2y=-9
(x-x)+(-y-2y)=-9
-3y=-9

2. Then, divide both sides of the equation by -3.


(-3y)/(-3)=(-9)/(-3)
y=3

Therefore, the value of y is 3.

3. To solve for x, we can substitute the value of "y" into any of the two equations.


x-y=12
x-3=12

Add 3 on both sides of the equation.


x-3+3=12+3
x=15

Therefore, the value of x is 15.

To summarize, x = 15 and y = 3.

User Glaucon
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