Evaluate

$(421)^{2}$

Evaluate

$(65)^{2}$

On dividing $p(x)=2 x^{3}-3 x^{2}+a x-3 a+9$ by $(x+1),$ if the remainder is $16,$ then find the value of $a$. Then, find the remainder on dividing $p(x)$ by $x+2$

Factorise each of the following

$8 x^{3}+343 y^{3}+84 x^{2} y+294 x y^{2}$

The following expressions are polynomials? Justify your answer:

$\frac{1}{x+1}$

Determine the degree of each of the following polynomials:

$y^{3}\left(1-y^{4}\right)$