Question

Which method would you use to solve this system of equations?

y = -2x + 9
-8x + 7y = -3
graphing
elimination
substitution
Falcon

Answer 1

substitution

Explanation:

y = - 2x + 9 → (1)

- 8x + 7y = - 3 → (2)

substitute y = - 2x + 9 into (2)

- 8x + 7(- 2x + 9) = - 3

- 8x - 14x + 63 = - 3

- 22x + 63 = - 3 ( subtract 63 from both sides )

- 22x = - 66 ( divide both sides by - 22 )

x = 3

substitute x = 3 into (1)

y = - 2(3) + 9 = - 6 + 9 = 3

solution is (3, 3 )