Respuesta :

Step-by-step explanation:

x+3y=12--(1)

x=-6y--(2)

put (2) in (1)

-6y+3y=12

-3y=12

divide both sides by -3

y=(12/-3)

y=-4

put y=-4 in (1)

x+3(-4)=12

x-12=12

x=12+12

x=24