[3x/(x-1) - x/(x+1)] × (x^2 - 1)/x
其中x= 根号2 - 2
[3x/(x-1) - x/(x+1)] × (x^2 - 1)/x
其中x= 根号2 - 2
原式={[3x(x+1)-x(x-1)]/(x-1)(x+1)}*(x-1)(x+1)/x
=3x+3-x+1
= 2x+4
当x=根号2 - 2
原式=2根号2
原式化为3(x+1)-(x-1)
代入得原式为2*根号2
通分[3x/(x-1) - x/(x+1)] × (x^2 - 1)/x=3(X+1)-X-1=2X+2