Question

x-2y=-7 x-3y=9 alguem que possa me ajudar?

Answer 1

x-2y=7 (-1)
x-3y=9

-x+2y=7
x-3y=9
(corta o x)

-y=16
y=-16

x-2y=-7
x-2.(-16)=-7
x=32-7
x=25

Answer 2

x-2y= -7  >>   x = -7 +2y ( A )

x-3y= 9  usando ( A )  -7 +2y - 3y = 9 >> 2y - 3y= 9 +7>> -y= 16>> y= -16

x-2.(-16)= -7 >> x + 32= -7>> x = -7-32 >> x = - 39

-39 -3.(-16)=9>> -39+48= 9       resposta confirmada x=-39  y= -16