1)10a²b-2a² +5ab² -ab=2a²(5b-1) +ab(5b-1) =a(5b-1)(2a+b).
2) 2x³ -3x²y -4x+6y =x²(2x-3y) -2(2x-3y)=(2x-3y(x² -2).
3) x²y -x +xy²-y=x(xy-1) +y(xy-1) =(xy-1)(x+y).
4) am² -an-bm²+cn-cm²+bn=am² -bm²-cm² -an+bn+cn =m²(a -b-c) -n(a-b-c) =
(a -b-c)(m² -n).
5) 0,81y^10) - 400*z^12)= (0,9y^5)² - (20z^6)² =(0,9y^5 -20z^6) (0,9y^5 +20z^6).
6) -1+49(a^4)*(b^8) = (7*a²*b^4)² -1 =(7*a²*b^4 -1)(7*a²*b^4+1).