What is the range of f (x) = 3x + 9?

Answer: - 21, - 18, - 9, - 6, 15

Explanation:

The range is all the values the function can achieve by using x in from its domain, so we just plug in all the numbers in the domain here;

f (-4) = 3 (-4) - 9 = - 12 - 9 = - 21

f (-3) = 3 (-3) - 9 = - 9 - 9 = - 18

f (0) = 3 (0) - 9 = 0 - 9 = - 9

f (1) = 3 (1) - 9 = 3 - 9 = - 6

f (8) = 3 (8) - 9 = 24 - 9 = 15

So the range is the set {-21, - 18-, - 9, - 6, 15}