Respuesta :

x-y=7
y=3x+12
y-3x=12
+
-y+x=7
=
-2x=19
x=-9.5
y=-16.6. Hope it help!

Answer: x=-9.5

y=-16.5

Step-by-step explanation:

Hi, to solve this problem we have to apply the substitution method:

x-y =7 (a)

y=3x+12(b)

Replacing the value of "y" in (a) for (b):

x -(3x+12)=7

x-3x-12=7

x-3x =7+12

-2x =19

x=19/-2

x=-9.5

Replacing the value of "x" in (b)

y=3x+12

y=3(-9.5)+12

y= -28.5+12

y=-16.5

Feel free to ask for more if needed or if you did not understand something.