Ok, a fun hack
if f⁻¹(a)=b then f(b)=a
so if f⁻¹(7)=b then f(b)=7
to find b, find x such that f(x)=7
7=0.5(3)^x
times both sides by 2 (or divide both sides by 0.5)
14=3^x
take log₃ of both sides

$23.1 i think is the answer not sure
X=15 since you subtract 1 from 27 then subtract 12 from 27 and you get 15
mighsevhrificjdjsjwbwbjsj oshwbebrbfjvs