f(x+1)=x2+4x-5怎么变成f(x)

f(x+1)=x2+4x-5怎么变成f(x)
f(x+1)=x2+4x-5怎么变成f(x)

f(x+1)=x2+4x-5怎么变成f(x)
f(x+1)=x2+4x-5
=(x+1)^2+2(x+1)-8
所以
f(x)=x^2+2x-8

f(x+1)=x2+4x-5=（x+1)^2+2(x+1)-8
f(x)=x^2+2x-8

f(x+1)=x2+4x-5=(x+2)^2-9=[(x+1)+1]^2-9
f(x)=(x+1)^2-9=x^2+2x-8

令t=x+1,则：x=t-1
f(t)=(t-1)^2+4(t-1)-5=t^2-2t+1+4t-4-5=t^2+2t-8
f(x)=x^2+2x-82