A.
For Company A
Let
be the total charges of Company A, and let
be the number of loads; we also know that the additional service charge is $8. So, putting all together into an equation we get:

For Company B
Let
be the total charges of Company B, and let
be the number of loads; we also know that the additional service charge is $4. So, putting all together into an equation we get:

Answer
Equations representing the total charges for a certain number of loads of laundry:
Company A:

Company B:

B.
Here we just need to replace
with 5 in each equation and compare the totals.
For Company A




Company A charges $108 for 5 loads of laundry.
For Company B




Company B charges $124 for a 5 load laundry.
Answer
Company A charges less for 5 loads of laundry than Company B; in fact, Company A charges $16 less than Company B.
C.
First we are going to find how much each Company charges for 9 loads of laundry; then, we are going to subtract the total charges from Company A from the total charges of Company B.
For Company A



Company A charges $188 for a 9 load laundry.
For Company B




Company B charges $220 for a 9 load laundry.
Difference: $220 - $188 = $32
Answer
Company A charges $32 than Company B to clean 9 loads of laundry.