Question

Solve each system by substitution.

Answer 1

-8x + 4y = 20
-8x = 20 - 4y

Subtitute -8x with 20-4y
-8x + 7y = 5
(20-4y) + 7y = 5
20 + 3y = 5
3y = 5 - 20
3y = -15
y = -15/3
y = -5

Find x
-8x = 20 - 4y
-8x = 20 - 4(-5)
-8x = 20 + 20
-8x = 40
x = 40/-8
x = -5