Question

一道求函数解析式的题目,详解若f（x+1）=x2-4,那么f（x-1）的表达式为_______2为x的次幂在线等

Answer 1

f（x+1）=x2-4

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

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

=x^2-4x

或

假设t-1=x+1

x=t-2

f(t-1)=(t-2)^2-4

=t^2-4t

所以f(x-1)=x^2-4x