Solve the system of linear equations using the elimination method

Question

Solve by using the elimination method:

y = x^2 + 3x - 8

y = x + 7

Answer 1

Subtracts them:

0 = x^2 + 3x - 8 - ( x + 7)

= x^2 + 3x -8 - x - 7

= x^2 + 2x -15

= (x + 5)(x-3)

so x=-5 or x = 3

(-5,2) or (3,10)