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.

`(-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.