solve the system of equations by substitution -4x + 4y = -40 and y = 3x - 4

Answer 1

Substitute y = 3x - 4 into the first equation:

-4x + 4(3x - 4) = -40
-4x + 12x - 16 = -40
8x - 16 = -40
8x = -24
x = -3

Now, substitute x = -3 back into the second equation to solve for y:

y = 3(-3) - 4
y = -9 - 4
y = -13

Therefore, the solution to the system of equations is x = -3 and y = -13.