Get x on one side then you can use substitution So, change x+3y=3 to x= -3y+3 Then plug in x to other equation to find y 2(-3y +3)-3y=-12 -6y + 6 -3y = -12 -9y = -18 Divide both sides by negative nine to find y y = 2 Then plug in to original equation to find x x + 3(2) = 3 x + 6 = 3 x = -3 So, y = 2 and x = -3