Find the value of $a$,if $x-a$ is a factor of $x^{3}-a x^{2}+2 x+a-1$.

Expand: $(3x + 7y)(3x - 7y)$

Factorise $9x^{2} + 42x + 49$.

With the help of the remainder theorem,find the remainder when the polynomial $p(x) = x^{3} + x^{2} - 26x + 24$ is divided by the divisor $x - 4$.

Classify the following as linear,quadratic,or cubic polynomial:
$8x^{3} - 343$

Factors of $x^{2}-23x+120$ are.........