1.a^3-ab^3= a(a^2-b^3)
2.0.49a^2-49b^2= 0.49[a^2-(10b)^2]=0.49(a-10b)(a+10b)
3.2ab^3-2abc^2= 2ab(b^2-c^2)=2ab(b-c)(b+c)
4.16a^2 - 25b^2 x^2= (4a)^2-(5bx)^2=(4a+5bx)(4a-5bx)
5.(a-1)+a^2(1-a)= (a-1)(1-a^2)=-(a-1)^2(a+1)
6.m^2(a-2m)^2-m(2m-a)= m(a-2m)[m(a-2m)+1]
7.4x^2-9y^2= (2x)^2-(3y)^2=(2x-3y)(2x+3y)
8.9a^6-4b^4= (3a^3+2b^2)(3a^3-2b^2)