Consider the given function. f(x)=−3x−3 Substitute 3 for f(x) −3x−3=3 −3x=6 x=−2 Substitute -6 for f(x) −3x−3=−6 −3x=−3 x=1 Substitute -9 for f(x) −3x−3=−9 −3x=−6 x=2 Substitute -18 for f(x) −3x−3=−18 −3x=−15 x=5 Therefore, the domain of the function is f={−2,1,2,5}