Notice that y = 2x, which means you can replace any y and turn them into 2x
x = -y + 6
x = -(2x) + 6
Move the x terms to the left and change the sign
x + 2x = 6
3x = 6
x = 2
Now that you know x, substitute them back into the first y = 2x
y = 2(2)
y = 4
Answer: x = 2, y = 4
