Three and six tenths
Hope I helped!
Answer:
(a)

(b)

(c)

Step-by-step explanation:
(a)
Simply evaluate (a+h) in the function:

(b)
Evaluate (a) in the function:

Using the previous answers lets calculate f(a+h)-f(a)

(c) To find the rate of change of f(a+1) when a=7 we need to calculate its derivate at that point:

Complementary angles sum to 90°. Supplementary angles sum to 180°.
First you need to make a multiplier for 100-2.1%, to do this you minus the values and divide it by 100:
100-2.1 = 97.9
97.9/100 = 0.979
Then you multiply all the questions by it:
$45 * 0.979 = $44.055
$765 * 0.979 = $748.935
$1300 * 0.979 = $1272.7
Hope this helps! :)