Answer:
1: 50 - (3(3) + 5.5(4))=x
2: okay so we know how much books are brought and how much each cost.
In this case paper backs are 3 dollars each and cost 3 dollars each. So 3 (3) is 9 dollars. The next scenario are hardbacks which are 5.50 each and Tom brought 4 of them. So that makes it 5.5(4) which is 22 dollars. So the total would be 9+22 which is 31 dollars. The question asks for change from a 50 dollar bill which you subtract and 50-31=19
The change would be 19 dollars