Factorise : $27 x^{3}+y^{3}+z^{3}-9 x y z$
Factorise : $6 x^{2}+5 x-6$
Factorise $y^2 -5y + 6$ by using the Factor Theorem.
Verify whether the following are zeroes of the polynomial, indicated against them.
$p(x)=2 x+1, \,\,x=\frac{1}{2}$
Factorise of the following : $27-125 a^{3}-135 a+225 a^{2}$