Question

已知f(x)=(3x-1)/(x+2),求y=f-1(x)的解析式

Answer 1

(x+1)f(x) =3x-1

xf(x)+f(x)=3x-1

3x-xf(x)=f(x)+1

(3-f(x))x=f(x)+1

∴x=[f(x)+1]/[3-f(x)]

∴f(x)的反函数=(x+1)/(3-x)