Respuesta :

{y=3x+1 |*5
{y=5x-3 |*(-3)

{5y=15x+5
{-3y=-15x+9
+___________
2y=14

{y=7
{7=3x+1

{3x=6
{y=7

{x=2
{y=7

The answer: C

:)