Find the zero of the polynomial in the following case:
$p(t) = 7t - 21$

On dividing $16x^2 - 24x + 9$ by $4x - 3$,find the remainder.

If the polynomials $az^{3}+4z^{2}+3z-4$ and $z^{3}-4z+a$ leave the same remainder when divided by $z-3$,find the value of $a$.

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

Factorise the following quadratic polynomial by splitting the middle term:
$x^{2}+2x-143$

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