Evaluate $103 \times 97$.

Which of the following expressions are polynomials in one variable and which are not? State the reason for your answer. If the given expression is a polynomial,state whether it is a polynomial in one variable or not.
$x^{2} + x - 3 + \frac{4}{x}$

Classify the following as a constant,linear,quadratic,or cubic polynomial:
$3$

Evaluate the following product without multiplying directly: $103 \times 105$.

Give possible expressions for the length and breadth of a rectangle whose area is given as $(20 x^{2}+22 x+6)$ square units,where $(x > 0)$.

Factorise the following:
$16 x^{2}+4 y^{2}+9 z^{2}-16 x y-12 y z+24 x z$