Question

先化简,再求值:(3x+4/x的平方-1-2/x-1)÷x+2/x的平方-2x+1,其中x是方程8x-5=3x的解

Answer 1

(3x+4/x的平方-1-2/x-1)÷x+2/x的平方-2x+1,

=[（3x+4-2(x+1))/(x^2-1)] *(x^2-2x+1)/(x+2)

=[（3x+4-2x-2)/(x-1)(x+1)] * (x-1)^2/(x+2)

=[（x+2)/(x-1)(x+1)] * (x-1)^2/(x+2)

=(x-1)/(x+1)

其中x是方程8x-5=3x的解

则有x=1

上式=(1-1)/(1+1)=0