数学题23和25，望大神立即解答。

23.(1+1/(a-3)÷(a？-4)/(2a-6)=(a-2)/(a-3)÷(a+2)(a-2)/2(a-3)=(a-2)/(a-3)×(a-3)/(a+2)(a-3)= 1/(a+2)

25.(x？+x)？-8(x？+x)+12=(x？+x)？-8(x？+x)+16-4=(x？+x-4)？-4=(x？+x-4+2)(x？+x-4-2)=(x？+x-2)(x？+x-6)=(x+2)(x-1)(x+3)(x-2)