Respuesta :

Yang100

Answer:

x=-19/2, -33/2. (-19/2, -33/2).

Step-by-step explanation:

x-y=7

y=3x+12

-------------

y=x-7

x-7=3x+12

x-3x-7=12

-2x-7=12

-2x=12+7

-2x=19

x=19/-2

-19/2-y=7

y=-19/2-7

y=-19/2-14/2

y=-33/2