Factorise $16 x^{2}-40 x y+25 y^{2}$.

The value of $249^{2}-248^{2}$ is

Find the zeroes of the polynomial in each of the following:
$h(y) = 2y$

If $x^{2}+kx+6=(x+2)(x+3)$ for all $x$,then the value of $k$ is

State whether the following statement is true or false:
In the polynomial $5x^{3} - 3x^{2} + 11x - 14$,the coefficient of $x^{3}$ is $3$.

Which of the following expressions is a polynomial,and state the reason? If an expression is a polynomial,state whether it is a polynomial in one variable or not: $x^{3}+3 x^{2} y+3 x y^{2}+y^{3}$