先化简,在求值:(3x/x+1-x/x-1)÷x-2/x²-1,其中选√3/2.

先化简,在求值:(3x/x+1-x/x-1)÷x-2/x²-1,其中选√3/2.
先化简,在求值:(3x/x+1-x/x-1)÷x-2/x²-1,其中选√3/2.

先化简,在求值:(3x/x+1-x/x-1)÷x-2/x²-1,其中选√3/2.
 

(3x/x+1-x/x-1)÷x-2/x²-1
=(3x/x+1-x/x-1)*(x-1)(x+1)/(x-2)
=x[3(x-1)-(x+1)]/(x-2)
=x(3x-3-x-1)/(x-2)
=x(2x-4)/(x-2)
=2x(x-2)/(x-2)
=2x
=2*√3/2
=√3

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

把x-2/x²-1分解因式得x-2/（x+1)(x-1)再把分解过的因式的倒数乘进去得

（3x/x+1）*（x+1)(x-1)/（x-2）-（x/x-1）*（x+1)(x-1)/（x-2）得
=3x(x-1)/(x-2)-x(x+1)/(x-2)
=[3x(x-1)-x(x+1)]/(x-2)
=2x
把x的值代进去即可