x - 2y = -4
3x + y = 9 x= - 2 ; y = 3 x= -6 ; y = 5 x= -5 ; y = 4 x= -6 ; y = -5. x + 2y + z = 7
3x + y + z = 5
2x + 3y -z =3 x = 2 ; y = 14 ; z =19 x =0 ; y =26 ; z = 39 x = -8 ; y = -26 ; z =-39 x =4 ; y = 16 ; z =-15. 10x +18y = -11
16x - 9y = -5 x = -2 ; y = -1/3 x = -1/2 ; y = -1/5 x = -1/6 ; y = -1/3 x = -1/2 ; y = -1/3 x = -1/7 ; y = -1/3.