Solve: x=3,y=4,z=x+yx = 3, y = 4, z = x+yx=3,y=4,z=x+y.
(3,4,7)(3, 4, 7)(3,4,7)
(3,4,12)(3, 4, 12)(3,4,12)
(4,3,7)(4, 3, 7)(4,3,7)
(0,0,7)(0, 0, 7)(0,0,7)