Question

已知f(1+√x)=x-1,求f(x)

用拼凑法!!在线等,急谢谢.

Answer 1

f(1+√x)=x-1
=(1+√x)(√x -1)
=(1+√x)(√x +1 -2)
所以 ：f(x)=x(x-2)

Answer 2

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

f(x)
=x(x-2)
=x²-2x