Factorise the following quadratic polynomials by splitting the middle term
$12 x^{2}+23 x+5$
Expand
$(3 x-1)(3 x+4)$
Find $p(1), p(2)$ and $p(4)$ for each of the following polynomials
$p(y)=y^{2}-5 y+4$
Factorise :
$84-2 r-2 r^{2}$
The polynomial $p(x)=x^{4}-2 x^{3}+3 x^{2}-a x+3 a-7$ when divided by $x+1$ leaves the remainder $19 .$ Find the values of $a .$ Also find the remainder when $p(x)$ is divided by $x+2.$