.5x+(9+a)x+2a-2
2.(1-a)(1-b)-4ab
3.a(b-c)+b(c-a)+c(a-b)
4.2x(2x+1)-y(y+1)
5.(x+1)(x+2)(x+3)(x+4)-120
6.[(x+y)-(x+y)]/3（x+y)
为次方,/为除号
1.原式= 5x+(9+a)x+2(a-1)
=[5x+(a-1)]*(x-2)
2.原式= 1-a-b-ab-4ab
=1-2ab-ab--a-b-2ab
= 1-ab)-(a+b)
=(1-ab+a+b)(1-ab-a-b)
3.原式=ab-ac+bc-ab+ac-bc
=b*(a-c)-ac*(a-c)-b(a-c)
=(a-c)[b(a+c)-ac-b]
=(a-c)[ab+bc-ac-b]
4.原式=4x+2x-y-y
=(2x+y)(2x-y)+(2x-y)
=(2x-y)(2x+y+1) .5x+(9+a)x+2a-2
2.(1-a)(1-b)-4ab
3.a(b-c)+b(c-a)+c(a-b)
4.2x(2x+1)-y(y+1)
5.(x+1)(x+2)(x+3)(x+4)-120
6.[(x+y)-(x+y)]/3（x+y)
为次方,/为除号
1.原式= 5x+(9+a)x+2(a-1)
=[5x+(a-1)]*(x-2)
2.原式= 1-a-b-ab-4ab
=1-2ab-ab--a-b-2ab
= 1-ab)-(a+b)
=(1-ab+a+b)(1-ab-a-b)
3.原式=ab-ac+bc-ab+ac-bc
=b*(a-c)-ac*(a-c)-b(a-c)
=(a-c)[b(a+c)-ac-b]
=(a-c)[ab+bc-ac-b]
4.原式=4x+2x-y-y
=(2x+y)(2x-y)+(2x-y)
=(2x-y)(2x+y+1)