724. 1)
(x+4)(x^2-20x+100)=
(x+4)(x-10)^2
2)
-(36-a^2)-2a(36-a^2)-
-a^2(36-a^2)=
(36-a^2)(-1-2a-a^2)=
= -(36-a^2)(a^2+2a+1)=
= -(36-a^2)(a+1)^2
3)
a^2b-a^2-ab^2+b^2=
(a^2b-ab^2)-(a^2-b^2)=
ab(a-b)-(a-b)(a+b)=
=(a-b)(ab-a-b)
4)
(m-n)(n-p)(n^2+np+p^2)-
-(n-p)(m-n)(m^2+mn+n^2)=
=(m-n)(n-p)(n^2+np+p^2-
-m^2-mn-n^2)=
=(m-n)(n-p)(np+p^2-m^2-mn)