Question

Use the substitution method to solve the system y = -2x + 1, -4x = —2y + 10.

Answer 1

Given y = -2x + 1, substitute into -4x = -2y + 10:

-4x = -2(-2x + 1) + 10
-4x = 4x - 2 + 10
-4x = 4x + 8
-8x = 8
x = -1

Then y = -2(-1) + 1 = 2 + 1 = 3.

Solution: (x, y) = (-1, 3). (Check: -4(-1) = 4 and -2(3)+10 = 4.)