Expand the following:

$(3 a-5 b-c)^{2}$

 …… is one of the factors of $p(x)=x^{3}-3 x^{2}+7 x-5$

If $x+2$ is a factor of $x^{3}+a x^{2}-x+30,$ find the value of $a$.

$(5 x+3)(5 x-3)=\ldots \ldots . .$

Find $p(1), p(2)$ and $p(4)$ for each of the following polynomials

$p(x)=x^{3}+9 x^{2}+23 x+15$