12x - 7y = 2 4x - 5y = 6
12x-7y=2 { 4x-5y=6 12x-7y=2 { 4x=6+5y |*3 12x-7y=2 { 12x=18+15y 18+15y-7y=2 { 12x=18+15y 8y=2-18=-16 { 12x=18+15y y=-2 { 12x=18-(15*(-2)) y=-2 { 12x=-12 y=-2 { x=-1