Factorise :

$a^{3}-2 \sqrt{2} b^{3}$

Which of the following expressions are polynomials in one variable and which are not $?$ State reason for your answer. If the given expression is a polynomial, state whether it is a polynomial in one variable or not

$x^{2}-8 x+15$

What are the possible expressions for the dimensions of a cuboid whose volume is given as $\left(2 x^{3}+15 x^{2}+33 x+20\right)$ cubic units? $(x>0)$

Factorise :

$x^{3}+x^{2}-4 x-4$

The value of the polynomial $5 x-4 x^{2}+3,$ when $x=-1$ is