а) а³-2a²+a-2 = a(a²+1)-2(a²+1) = (a²+1)(a-2).
б) 3x+9-xy-3y = 3(x+3)-y(x+3) = (x+3)(3-y).
в) ax+3ay+5x+15y = a(x+3y)+5(x+3y) = (x+3y)(a+5).
г) x⁵+2x⁴-x-2 = x⁴(x+2)-(x+2) = (x+2)(x⁴-1) = (x+2)(x²-1)(x²+1) =
(x+2)(x-1)(x+1)(x²+1).
д) ab+ac+a²+bc = b(a+c)+a(c+a) = b(a+c)+a(a+c) = (a+c)(b+a).
ж) 14xy+21y² = 7y(2x+3y).
з) 3y³-6y⁶ = 3y³(1-2y³).
и)y³+y⁴ = y³(1+y).