Решение:
316.
a) $$(5ab^2 + 4b^3)(3ab^3 - 4a^2) - 18a^2b^5 = 15a^2b^5 - 20a^3b^2 + 12ab^6 - 16a^2b^3 - 18a^2b^5 = -3a^2b^5 - 20a^3b^2 + 12ab^6 - 16a^2b^3$$
Ответ: $$-3a^2b^5 - 20a^3b^2 + 12ab^6 - 16a^2b^3$$
б) $$(7x^3y^2 - xy)(-2x^2y^2 + 5xy^3) + 12x^5y^4 = -14x^5y^4 + 35x^4y^5 + 2x^3y^3 - 5x^2y^4 + 12x^5y^4 = -2x^5y^4 + 35x^4y^5 + 2x^3y^3 - 5x^2y^4$$
Ответ: $$-2x^5y^4 + 35x^4y^5 + 2x^3y^3 - 5x^2y^4$$
B) $$(x^3 + x^2y + xy^2 + y^3)(x - y) – x^2y (x - y) = x^4 + x^3y + x^2y^2 + xy^3 - x^3y - x^2y^2 - xy^3 - y^4 - x^3y + x^2y^2 = x^4 - x^3y + x^2y^2 - y^4$$
Ответ: $$x^4 - x^3y + x^2y^2 - y^4$$
г) $$a^2(a^2 - b^2) - (a^3 - a^2b + ab^2 - b^3)(a + b) = a^4 - a^2b^2 - (a^4 + a^3b - a^3b - a^2b^2 + a^2b^2 + ab^3 - ab^3 - b^4) = a^4 - a^2b^2 - a^4 - a^3b + a^3b + a^2b^2 - a^2b^2 - ab^3 + ab^3 + b^4 = -a^2b^2 + b^4$$
Ответ: $$-a^2b^2 + b^4$$
д) $$2 - (-4x + 1)(x - 1) + 2(6x - 4)(x + 3) = 2 - (-4x^2 + 4x + x - 1) + 2(6x^2 + 18x - 4x - 12) = 2 + 4x^2 - 5x + 1 + 12x^2 + 28x - 24 = 16x^2 + 23x - 21$$
Ответ: $$16x^2 + 23x - 21$$
e) $$6(x + 1)(x + 1) + 2(x - 1)(x^2 + x + 1) - 2(x + 1) = 6(x^2 + 2x + 1) + 2(x^3 - 1) - 2x - 2 = 6x^2 + 12x + 6 + 2x^3 - 2 - 2x - 2 = 2x^3 + 6x^2 + 10x + 2$$
Ответ: $$2x^3 + 6x^2 + 10x + 2$$
ж) $$(x + 2)(x^2 - 2x + 4) - x(x - 3) (x + 3) = x^3 + 8 - x(x^2 - 9) = x^3 + 8 - x^3 + 9x = 9x + 8$$
Ответ: $$9x + 8$$
з) $$3(3x-1) (2x + 5) -6(2x - 1)(x + 2) = 3(6x^2 + 15x - 2x - 5) - 6(2x^2 + 4x - x - 2) = 18x^2 + 39x - 15 - 12x^2 - 18x + 12 = 6x^2 + 21x - 3$$
Ответ: $$6x^2 + 21x - 3$$
и) $$(x^2 + 2)(x^2 + 2) - (x - 2)(x + 2)(x^2 + 4) = x^4 + 4x^2 + 4 - (x^2 - 4)(x^2 + 4) = x^4 + 4x^2 + 4 - (x^4 - 16) = x^4 + 4x^2 + 4 - x^4 + 16 = 4x^2 + 20$$
Ответ: $$4x^2 + 20$$