Let f(x) = 5x-2.?

Question

Find
(a) f(4) – f(3);
(b) f(9)-f(8);
(c) f(12) – f(11).
(d) How do the results of (a) through (c) compare to the slope of the line that is the graph of f?

Answer 1

f(x) = 5x - 2

Answer 1:
f(4) = 20 - 2 = 18
f(3) = 15 - 2 = 13

18 - 13 = 5

Answer 2:
f(9) = 45 - 2 = 43
f(8) = 40 - 2 = 38

43 - 38 = 5

Answer 3:
f(12) = 60 - 2 = 58
f(11) = 55 - 2 = 53

58 - 53 = 5

Answer 4:
If x, increases by 1, f(x) increases by 5.

Answer 2

a. 18-13=5
b. 43-38=5
c. 58-53=5
d. If you add 1 to the x you go up by 5.