Question

Решите уравнение (х + 3) (2x - Зх + 9) = х^3 - Зх,

Answer 1

$2x {}^{2} - 3x {}^{2} + 9x + 6x - 9x + 27 = x {}^{3} - 3x \\ - x { }^{2} + 6x = x {}^{3} - 3x \\ - x {}^{2} + 6x + 3x - x {}^{3} = 0 \\ x {}^{3} + x {}^{2} - 9x = 0 \\ x(x {}^{2} + x - 9) = 0 \\ x1 = 0 \\ x {}^{2} +x - 9 = 0 \\ d = 1 {}^{2} + 4 \times 9 = 37 \\ x2.3 = \frac{ - 1 + - \sqrt{37} }{2}$