已知函数f(x+1)=x2-x+3,那么f(x-1)的表达式是

2024-12-26 22:05:35
推荐回答(2个)
回答1:

解:设t=x+1 则x=t-1 可得:
f(t)=(t-1)^2-(t-1)+3
=t^2-3t+5
可得:f(x)=x^2-3x+5
f(x-1)=(x-1)^2-3(x-1)+5
=x^2-5x+9

回答2:

f(x+1)=x^2-x+3=(x+1)^2-2x-1-x+3=(x+1)^2-3x+2=(x+1)^2-3(x+1)+5
所以f(x)=x^2-3x+5,所以f(x-1)=(x-1)^2-3(x-1)+5=x^2-5x+9