Solve: x+y=0,y=x+4x + y = 0, y = x + 4x+y=0,y=x+4.
(−2,2)(-2, 2)(−2,2)
(2,−2)(2, -2)(2,−2)
(0,0)(0, 0)(0,0)
(2,2)(2, 2)(2,2)