Answer:
Step-by-step explanation:
x = 6 + y
6 + y + y = 8
y = 1
x - 1 =6
x = 7
zx + zy = z(x + y) = 20
z = 2.5
If we multiply the top equation by -4 we can get rid of the x so:
-4x+20y=-12
4x-4y=12
Add these up
16y=0
Y=0
X=3