diketahui f(x) maka [tex]f ^{ - 1} (4)[/tex] [tex] \frac{3x - 1}{2x - 1} [/tex]

jawab

f(x) = (3x -1)/(2x - 1)

y  = (3x -1) /(2x - 1)
y(2x -1) = 3x - 1
2xy - y = 3x -1
2xy - 3x = y  - 1
x(2y -3) = (y -1)
x = (y -1)/(2y - 3)
f⁻¹ (x)  =  (x -1)/(2x - 3)
f⁻¹(4) =  (4 -1)/(8- 3) = 3/5