Решите два уравнения (подробно) 1)3х²+36=21х 2)2х²=х+21

3x² + 36 = 21x 3x² - 21x + 36 = 0 x² - 7x + 12 = 0 (x - 3)(x - 4) = 0 x = 3 or x = 4

2x² = x + 21 2x² - x - 21 = 0 2x² - 7x + 6x - 21 = 0 x(2x - 7) + 3(2x - 7) = 0 (x + 3)(2x - 7) = 0 x = -3 or x = 7/2