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

 -21, -18, -9, -6, 15

here's why
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}

Hope this helps! ;D