Just use the power rule:

We also could have use the fact that the integrand is even to write

I'll continue with this expression since it's easier to evaluate (if only a little):

You can write it as a proportion and then solve the proportion.
(2.5 hours is 150 minutes)
14 cars x cars
--------------- = -------------------
45 minutes 150 minutes
Then solve.
x=46.6666666
So that is about 47 cars
He would have 50$ in his account
0, No solution.
-4x-11=2 (x-3x)+13
-4x-11=2 (-2x)+13
-4x-11=-4x+13
-11 is not equal to 13 so there is no solution