Question

设函数f(x-1)=3x-1,则f(x)等于？

过程

Answer 1

设x-1=t,则x=t+1,所以f(t）=3（t+1)-1=3t+2再将t换回x即可，所以f(x)=3x+2

Answer 2

令t=x-1x=t+1所以f（t）=3（t+1）-1=3t+2所以f（x）=3x+2

Answer 3

把x+1代入f（x-1）得f（x）=3（x-1）-1，f（x）=3x-4

Answer 4

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