This is a bit of a guess, but I think probably a) +4 and also a) -215
Answer:

Step-by-step explanation:
The answer is
5q/2 or q×5/2
Pretty sure the answer is 18
3^2+3^2=9+9=18 (with a square root)
Step-by-step explanation:
The total bill will be the sum of the rent and the cost for the total time spent.
$15 + $6 * 2.5
$15 + $15
$30