Jika diketahui f(x) = 2x-3/ 4x+1 x tidak sama dengan -1/4 maka f^-1 (x) adalah

F(x) = (ax + b)/(cx + d) => f^-1(x) = (-dx + b)/(cx – a)
f(x) = (2x – 3)/(4x + 1) => f^-1(x) = (-x – 3)/(4x – 2) = (x + 3)/(2 – 4x) , x ≠ 1/2

cara lain
(2x – 3)/(4x + 1) = y
=> 2x – 3 = 4xy + y
=> 2x – 4xy = y + 3
=> x(2 – 4y) = y + 3
=> x = (y + 3)/(2 – 4y)
=> f^-1(x) = (x + 3)/(2 – 4x) , x ≠ 1/2