Question

y=2x-4

x+2y=12

Answer 1

Substitute 2x - 4 in for y in the equation x + 2y = 12

x + 2y = 12
x + 2 (2x - 4) = 12
x + 4x - 8 = 12
5x - 8 = 12
5x - 8 + 8 = 12 + 8
5x = 20
5x / 5 = 20 / 5
x = 4

Now substitute 4 in for x in the equation y = 2x - 4

y = 2x - 4
y = 2 (4) - 4
y = 8 - 4
y = 4

Solution is {4, 4}