Classify the following as a constant, linear,quadratic and cubic polynomials:

$4-5 y^{2}$

Evaluate

$205 \times 195$

Write the coefficient of $x^{2}$ in each of the following:

$(i)$ $\frac{\pi}{6} x+x^{2}-1$

$(ii)$ $3 x-5$

Degree of the polynomial $4 x^{4}+0 x^{3}+0 x^{5}+5 x+7$ is

If $a, b, c$ are all non-zero and $a+b+c=0,$ prove that $\frac{a^{2}}{b c}+\frac{b^{2}}{c a}+\frac{c^{2}}{a b}=3$