Find the value of the polynomial $x^{2}-7 x+12$ at.

$x=\frac{1}{2}$

From the following polynomials find out which of them has $(x-1)$ as a factor

$x^{3}+6 x^{2}-9 x-14$

Write the following cubes in expanded form

$(4 x-3 y)^{3}$

Expand

$(x+2 t)(x-5 t)$

Factorise :

$a^{3}-8 b^{3}-64 c^{3}-24 a b c$