#17) 8 cubic feet.
#19) 5 miles.
There are 2 ways that spring to mind.
One is to use the definition of the derivative at a point:

In this case,
and
. Then

- - -
If you don't know about derivative yet (I would think you do, considering this is for a midterm in AP Calc, but I digress), the other way is to rely on algebraic manipulation. Multiply the numerator and denominator by the conjugate of the numerator to get

This is continuous at
, so the limit is the value of the expression at
:

Answer:
(6x + 2) + 40 = 90
Step-by-step explanation:
Answer:
Angle C = 55°
Do you want an explanation