Question

已知f(x+1)=x-3x+2,求f(x)

Answer 1

令x+1=t x=t-1
代入得到的f(t)就是f(x'

Answer 2

Answer 3

令t=x+1,得x=t-1,故f(t)=(t-1)^2-3*(t-1)+2=t^2-5t+6,然后把t换成x，就求出来了

追答

感谢