Question

Find the zero of the polynomial : x³+ 2x² - 5x - 6

Answer 1

$$x^3+ 2x^2 - 5x - 6=0$$

$$(x^3+x^2)+(x^2+x)+(-6x-6)=0$$

$$x^2(x+1)+x(x+1)-6(x+1)=0$$

$$(x+1)(x^2+x-6)=0$$

$$(x+1)(x-2)(x+3)=0$$

$$x_1=-3, x_2=-1, x_3=2$$

Zeros: $-3, -1, 2$