Question

Y-0.8x=0.5
5y-2.5-4x

Answer 1

x = -1

Explanation:
y-0.8x=0.5

5y-2.5-4x

Get y by itself.
y = 1.3

Put 1.3 into the second equation

5(1.3) - 2.5 - 4x
6.5-2.5 - 4x
4 - 4x = 0
Get x by itself
-4x = 4
x = -1

I hope this was able to help you :D