Question

先化简,再求值:x^2+2x+1/x+2 ÷x^2-1/x-1 - 1-x-x^2/x+2,其中x=2014

Answer 1

解

(x²+2x+1)/(x+2)÷(x²-1)/(x-1)-(1-x-x²)/(x+2)

=(x+1)²/(x+2)÷(x-1)(x+1)/(x-1)-(1-x-x²)/(x+2)

=(x+1)²/(x+2)×1/(x+1)-(1-x-x²)/(x+2)

=(x+1)/(x+2)-(1-x-x²)/(x+2)

=(x+1-1+x+x²)/(x+2)

=(x²+2x)/(x+2)

=x

=2014