Given f (x) = x+5 all over 3, solve for f^-1 (3) (A. - 1; B. 14; C. 18; D. 21)

f^-1 means finverse

find finverse then subsitute 3 for x

to solve

replace f (x) with y

solve for x

switch x with y

replace y with finverse or f^-1

f (x) = (x+5) / 3

y = (x+5) / 3

3y=x+5

3y-5=x

3x-5=y

finvers=3x-5

fiinverse (3) = 3 (3) - 5

finverse (3) = 9-5

finverse (3) = 4

why is it not listed again