Reflection over the y-axis = change 
Compress by a factor of k = multiply by k
So, in your case, we first change the sign of the argument. Note that this has no effect, because f(x) is symmetric with respect to the y-axis:

Then, we compress the function, multiplying it by the scaling factor:

3/20 left to read. If you start 85/100 you take 100-85 and get 15, then you end up 15/100 which reduces to 3/20.
The volume is 1494.35
The formula is length times height adding the bases than divided it by 2