Question

1.已知+f(-x-1)=9x^2+5x-4,+求+f(x)

Answer 1

加号太多，是不是f(-x-1)=9x^2+5x-4
f(-x-1)=f[-(x+1)]
=9x^2+5x-4
=(9x-4)(x+1)
=[9(x+1)-13](x+1)

=-[-9(x+1)+13][-(x+1)]
=[-9(x+1)+13][-(x+1)]
f(x)=x(9x+13)=9x²+13x

Answer 2

f(-x-1)=9x²+5x-4
f(-x-1)=9(x+1)²-13(x+1)

f(-(x+1))=9(x+1)²-13(x+1)

f(x)=9x²+13