Упростите выражение:
1) $15a * \frac{a + 4}{3} + 12a^2 * \frac{5 - 2a}{6}$;
2) $24c^3 * \frac{c^2 + 2c - 3}{8} - 18c^2 * \frac{c^3 - c^2 + 2}{9}$;
3) $34x * \frac{x - y}{17} - 45y * \frac{x - 2y}{15} - y(6y - 5x)$.
$15a * \frac{a + 4}{3} + 12a^2 * \frac{5 - 2a}{6} = 5a(a + 4) + 2a^2(5 - 2a) = 5a^2 + 20a + 10a^2 - 4a^3 = -4a^3 + 15a^2 + 20a$
$24c^3 * \frac{c^2 + 2c - 3}{8} - 18c^2 * \frac{c^3 - c^2 + 2}{9} = 3c^3(c^2 + 2c - 3) - 2c^2(c^3 - c^2 + 2) = 3c^5 + 6c^4 - 9c^3 - 2c^5 + 2c^4 - 4c^2 = (3c^5 - 2c^5) + (6c^4 + 2c^4) - 9c^3 - 36c^2 = c^5 + 8c^4 - 9c^3 - 4c^2$
$34x * \frac{x - y}{17} - 45y * \frac{x - 2y}{15} - y(6y - 5x) = 2x(x - y) - 3y(x - 2y) - y(6y - 5x) = 2x^2 - 2xy - 3xy + 6y^2 - 6y^2 + 5xy = 2x^2 + (-2xy - 3xy + 5xy) + (6y^2 - 6y^2) = 2x^2 + 0 + 0 = 2x^2$
Пожауйста, оцените решение
