y = 2x-3 x + y = 18 Since you already know what y is equal to, we can plug that in into the second equation. x + (2x-3) = 18 x + 2x -3 = 18 3x -3 = 18 Add 3 to both sides of the equation. (By doing this, we can isolate the 3x on the left side by getting rid of the -3) 3x = 21 Divide 3 on both sides x = 7
