Replace the f(x) with y and proceed to make x the subject: y=1/4x-12 y+12=1/4x To ÷1/4 on both sides, ×4 on both sides 4(y+12)=x 4y+48=x Now swap y with x and replace the isolated x with f(x) to get the inverse function: [tex] {f}^{ - 1}(x) = 4x + 48 [/tex]
