Answer:
no solution
Explanation:
Since you are using substitution, you will plug in one of the variables using one of the equations.
y=x+4
x-y=8
put the y from above into the y below
x-(x+4)=8
Now, solve the equation
x-x-4=8
Put x's together
-4=8
-4 does not equal 8, so this system of equations has no solution