Question

How do you solve the system `8x + 3y= -9` and `-8x + y = 29` by elimination?

Answer 1

Given
`"[1] "8x+3y=-9`
`"[2] "-8x+y = 29`

Add `"[1] + [2]"`
`"[3] "(0)x + 4y = 20`

Which implies
`"[4] "y = 5`

Substituting `"[4] "` back into `"[1]"`
`"[5] "8x +3(5) = -9`

Gives
`"[6] " x=-3`

So the solution to the given pair of equations is
`(x,y) = (-3,5)`