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:

1. =
2.
3.q+4=-4
I don't know number 2
Answer:
-3 is the answer.
Step-by-step explanation:
=2(-1+3)-7
=2(2)-7
=4-7
=-3
Hope it will help you :)
To convert a percent to a decimal, divide the percent by 100.
0.8/100 = 0.008 <<<<<< answer.