Write the coefficients of $x^2$ in each of the following:
$(i)$ $2+x^2+x$
$(ii)$ $2-x^2+x^3$

Factorise: $2x^2 + y^2 + 8z^2 - 2sqrt{2}xy + 4sqrt{2}yz - 8xz$

Which of the following expressions are polynomials in one variable and which are not? State reasons for your answer: $4 x^{2}-3 x+7$.

Verify whether the following is a zero of the polynomial indicated against it:
$p(x) = 5x - \pi, \, x = \frac{4}{5}$

Find the zero of the polynomial: $p(x) = ax, a \neq 0$.

Factorise: $2y^{3} + y^{2} - 2y - 1$