Factorise $: 49 x^{2}-121$

Check whether the polynomial

$p(x)=x^{3}+9 x^{2}+26 x+24$ is a multiple of $x+2$ or not.

With the help of the remainder theorem. examine whether $x+2$ is a factor of the polynomial $x^{3}+9 x^{2}+26 x+24$ or not.

Factorise $x^{2}-7 x+12$ by using the factor theorem.

Factorise

$16 x^{2}-16 x-21$