-3x+y=-5 x+y=1

-3x+y=-5 x+y=1 y=-5+3x x+-5+3x=1 4x=6 x=6/4=1,5 1,5+y=1 y=1-1,5=-0,5

-3x+y=-5 x+y=1 I-y -3x+y=-5 x=1-y -3(1-y) +y=-5 x=1-y -3+3y+y=-5 x=1-y -3+4y=-5 I+3 x=1-y 4y=-2 I:4 x=1-y y=1/2 x=1-1/2 y=1/2 x=1/2