Question

Me ajudem por favor 3x-3y=21 2-y=5

Answer 1

{2x-y=5 ===> y=2x-5

{3x-3y=21 :(3)

x - y = 7

x -(2x-5)=7

x-2x+5 = 7

-x = 2

x = -2 ✓===> y=2x-5 = 2(-2)-5=-4-5= -9 ✓