Since you have y alone on one side of the equation......
Use substitution and plug in 1/2x-4 for y in the other equation.

Distribute

Combine like terms

Add 8 to both sides

Divide by 4
and 
Plug this value in for x

Simplify

Multiply everything by 8 and simplify

Divide.....

Your answers are:

7*y - 5*(4-2y) = 7y - 20 +10y = 17y-20 = 31,
y =3, x = -2.
Weird 20 min without answer!
Answer:i try checking the internet
Step-by-step explanation:
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