x的平方-x-2分之x的平方-1除以2x-4分之x
=(x+1)(x-1)/(x-2)(x+1)÷x/2(x-2)
=(x-1)/(x-2) * 2(x-2)/x
=2(x-1)/x
如果本题有什么不明白可以追问,