Find $p(1), p(2)$ and $p(4)$ for each of the following polynomials

$p(x)=x^{3}+9 x^{2}+23 x+15$

Factorise :

$x^{2}+9 x+18$

What should be added to $p(x)=x^{2}-8 x+10$ so that the resulting polynomial is divisible by $x-3 ?$

Multiply $x^{2}+4 y^{2}+z^{2}+2 x y+x z-2 y z$ by $(-z+x-2 y)$

Classify the following as linear, quadratic or cubic polynomial

$5 t+3$