#### Answer

f(1)=-12
f(2)=-15
f(3)=-18
f(4)=-21

#### Work Step by Step

f(x)=-3x-9
f(1)=-3(1)-9 =-12
f(2)=-3(2)-9 =-15
f(3)=-3(3)-9 =-18
f(4)=-3(4)-9 =-21
*You just plug the new number into each of the x's in the original function and then simplify to find your answer.