Which of the following expressions is a polynomial, state the reason ? If an expression is polynomial, state whether it is a polynomial in one variable or not

$3 x^{2}+5 x-7+\frac{8}{x}$

Without actually calculating the cubes, find the value of each of the following

$(0.2)^{3}-(0.3)^{3}+(0.1)^{3}$

Write the degree of the following polynomials

$11-2 y^{2}$

Evaluate

$(65)^{2}$

For the polynomial $p(x),$ if $p(7)=0,$ then $\ldots$ is............ a factor of $p(x) .$

Factorise :

$1+64 x^{3}$