Write the zeros of the polynomial

$f(x)=x^{2}-x-6$

$=x^{2}-3 x+2 x-6$

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

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

$f(x)=0 \Rightarrow(x-3)(x+2)=0$

$\Rightarrow(x-3)=0$ or $(x+2)=0$

$\Rightarrow x=3$ or $x=-2$

So, the zeros of f(x) are 3 and −2.