jika f-1 (4x+5) = 8x+12, maka f(x)

f^-1 (4x+5) = 8x + 12
f(8x+12) = 4x + 5
f(x) = 4((x-12)/8) + 5
f(x) = 1/2 x - 6 + 5
f(x) = 1/2 x - 1
f(x) = (x-2)/2

f^-1(4x + 5) = 8x + 12

>> maka dibalik

f(8x + 12) = 4x + 5

>> 8x + 12 menjadi x, dipindah

f(x) = 4((x - 12) / 8) + 5
f(x) = 4((x - 12) / 8) + 5
f(x) = (4/8x - 6) + 5
f(x) = 4/8x - 6 + 5
f(x) = 4/8x - 1
f(x) = 1/2x - 1

Maaf kalau salah