Question

Решите уравнение
$x^{3} + 3x^{2}- 25 x^{} -75=0$

Answer 1

$x^{3} + 3x^{2}- 25 x^{} -75=0\\x^2(x+3)-25(x+3)=0\\(x^2-25)(x+3)=0\\(x+5)(x-5)(x+3)=0\\x_{1,2}=pm5;quad x_3=-3$