5ax+5bx+3ay+3by
解法：=5x(a+b)+3y(a+b)
=(5x+3y)(a+b)
2. x3-x2+x-1
解法：=(x3-x2)+(x-1)
=x2(x-1)+(x-1)
=(x-1)(x2+1)
3. x2-x-y2-y
解法：=(x2-y2)-(x+y)
=(x+y)(x-y)-(x+y)
=(x+y)(x-y+1)
4、758²—258² =(758+258)(758-258)=1016*500=508000
5、3ab^2-9a^2b^2+6a^3b^2
=3ab^2(1-3a+2a^2)
=3ab^2(2a^2-3a+1)
=3ab^2(2a-1)(a-1)
6、x^2+3x-40
=x^2+3x+2.25-42.25
=(x+1.5)^2-(6.5)^2
=(x+8)(x-5)．
7、3ab^2-9a^2b^2+6a^3b^2
=3ab^2(1-3a+2a^2)
=3ab^2(2a^2-3a+1)
=3ab^2(2a-1)(a-1)
8、5-7(a+1)-6(a+1)^2
=-[6(a+1)^2+7(a+1)-5]
=-[2(a+1)-1][3(a+1)+5]
=-(2a+1)(3a+8);
9、-4x^3 +6x^2 -2x
=-2x(2x^2-3x+1)
=-2x(x-1)(2x-1);
10、6(y-z)^2 +13(z-y)+6
=6(z-y)^2+13(z-y)+6
=[2(z-y)+3][3(z-y)+2]
=(2z-2y+3)(3z-3y+2).
供参考