Tentukan invers dari f, nilai f^-1(3) adalah

f(x) = (2x+1)/3x+4
misal f(x) = y
y(3x+4) = 2x+1
3xy+4y = 2x+1
3xy-2x= -4y+1
x(3y-2)= -4y +1
x= (-4y+1)/3y-2
f^-1(x) = (-4x+1)/3x-2
maka
f^-1(3)= (-4(3) +1 ) / 3(3)-2
= -11/ 7
semoga membantu. :)

Mapel : Matematika
Kelas : X SMA
Bab : Fungsi Invers

Rumus Cepat :
f(x) = (ax + b)/(cx + d)
f¯¹(x) = (-dx + b)/(cx - a)

Pembahasan :
f(x) = (2x + 1)/(3x + 4)
f¯¹(x) = (-4x + 1)/(3x - 2)
f¯¹(x) = [-(4x - 1)]/[-(2 - 3x)]
f¯¹(x) = (4x - 1)/(2 - 3x)
f¯¹(3) = (4.3 - 1)/(2 - 3.3)
f¯¹(3) = - 11/7