1.a2·(-a)5·(-3a)3
2.[(am)n]p
3.(-mn)2(-m2n)3
4.(-a2b)3·(-ab2)
5.(-3ab)·(-a2c)·6ab2
6.(-ab)3·(-a2b)·(-a2b4c)2
7.(3m-n)(m-2n).
8.(x+2y)(5a+3b).
9.5x(x2+2x+1)-(2x+3)(x-5)
10. (-2x-5)(2x-5)
11. -(2x2+3y)(3y-2x2)
12. (a-5) 2-(a+6)(a-6)
13. (2x-3y)(3y+2x)-(4y-3x)(3x+4y)
14. 3(2x+1)(2x-1)-2(3x+2)(2-3x)
15. (x+y)(x-y)(x2+y2)
16.
17.
18. (x+4)(x+7)
19. (x-3)(x+5)
20. (2x+3)(3x-2)