设f(x-1)=3x-1,则f(x)=_.

问题描述:

设f(x-1)=3x-1,则f(x)=______.

设x-1=t,则x=t+1,代入f(x-1)=3x-1得,
f(t)=3(t+1)-1=3t+2,
∴f(x)=3x+2,
故答案为:3x+2.