2. Разложите на множители: 1) 16x5y7 - 24x6y4; 2) (c² + 8)² + c(c² + 8); 3) ab-ac-7b+7c; 4) 9x5 +12x²y4 – 15x3y - 20y.

Ответ:

1. $$ 16x^5y^7 - 24x^6y^4 = 8x^5y^4(2y^3 - 3x) $$
2. $$ (c^2 + 8)^2 + c(c^2 + 8) = (c^2 + 8)(c^2 + 8 + c) $$
3. $$ ab - ac - 7b + 7c = a(b - c) - 7(b - c) = (a - 7)(b - c) $$
4. $$ 9x^5 + 12x^2y^4 - 15x^3y^8 - 20y^{12} = 3x^2(3x^3 + 4y^4) - 5y^8(3x^3 + 4y^4) = (3x^2 - 5y^8)(3x^3 + 4y^4) $$