a) {y=5 x+y=5 b) {x+y=3 x+2y=4

a) {y=5 x+y=5   y=5 x+5=5   y=5 x=0 b) {x+y=3 x+2y=4   x=3-y 3-y+2y=4   x=3-y y=1   x=3-1 y=1   x=2 y=1

y=5 x+y=5   y=5 x=5-5   y=5 x=0   x+y=3 x+2y=4   x=3-y 3-y+2y=4   x=3-y y=1   x=2 y=1

{y=5 x+y=5 {y=5 x+5=5 {y=5 x=0 b) {x+y=3 x+2y=4 {x=3-y 3-y+2y=4 {x=3-y y=1 {x=2