Question

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

Answer 1

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

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.

$\frac{-3y}{-3}=\frac{-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.