Question

Решите уравнение Х³+2х²-9х-18=0

Answer 1

. . . .
x^2(x+2)-9(x+2)=0
(x^2-9)(x+2)=0
x^2=9 и х=-2
x=+-3
ответ:+-3;-2

Answer 2

X^3 + 2x^2 - 9x - 18 = 0 
x^2(x+2) -9(x+2) = 0
(x+2)(x^2-9) = 0
(x+2)(x-3)(x+3)=0
x_1 = -2
x_2 = 3
x_3 = -3