5.75a + 6.5c = 53.25
a + c = 9
c = 9 - a
5.75a + 58.5 - 6.5a = 53.25
5.25 = 0.75a
a = 7
7 + c = 9
c = 2
she bought 7 apple pies
please give brainliest
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:

Answer:
6.75
Step-by-step explanation: