令t=x+1,则x=t-1f(x+1)=f(t)=x²-1=(t-1)²-1=t²-2t所以f(x)=x²-2x
f(x+1)=x²-1=(x+1-1)²-1=(x+1)²-2(x+1)+1-1=(x+1)²-2(x+1)∴f(x)=x²-2x
f(x)=x²-2x解析:f(x+1)=x²-1=(x+1-1)²-1=(x+1)²-2(x+1)+1-1=(x+1)²-2(x+1)∴ f(x)=x²-2x