Salesperson A made $7428.30
Salesperson B made $6859.20
Salesperson A made more commission this month and made $7428.30
5 C + 3 < 28 a - 4 C - 214
a>9c +31
------------
28. 4
C >28a-21
------
9
Answer: x=4
Steps: (I am assuming your question has a typo in it and by "c" you meant "x")
The rational expression equals zero

only when the numerator equals 0 (the denominator cannot ever be zero):

and that happens only for x=4