Respuesta :
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.