令(3x+2)/2x-1＝1
则x=-3
f(1)=(-3)^2-1
=8
令(3x+2)/2x-1＝y
则x=(-2-y)/(3-2y)
f(y)=[(-2-y)/(3-2y)]^2-1
f(x)=[(-2-x)/(3-2x)]^2-1