3a平方+5-2a平方-2a+3a-8

=(3a-2)/(3a-4)(a-1)-(3a-4)/(3a-2)(a-1)
=[(3a-2)²-(3a-4)²]/(3a-2)(3a-4)(a-1)
=(3a-2+3a-4)(3a-2-3a+4)/(3a-2)(3a-4)(a-1)
=(6a-6)*2/(3a-2)(3a-4)(a-1)
=12(a-1)/(3a-2)(3a-4)(a-1)
=12/(3a-2)(3a-4)
=12/(9a²-18a+8)

(a-1)(3a+2)=0
a=1或a=-2/3

用十字相乘法比较简单.
1 -1
3 1
3a²-2a-1=(a-1)(3a+1)

(3a平方b-ab平方)-(ab平方+3a平方b)
=3a²b-ab²-ab²-3a²b
=-2ab²

3a²-3ab+2ab-2b²-a+b=3a²-ab-2b²-a+b=(3a+2b)(a-b)-(a-b)=(3a+2b-1)(a-b)