Find the value of the polynomial $5x -4x^2+ 3$ at $x = -\,1$.
$6$
$-6$
$5$
$4$
Factorise : $2 x^{2}+y^{2}+8 z^{2}-2 \sqrt{2} x y+4 \sqrt{2} y z-8 x z$
Factorise : $x^{3}+13 x^{2}+32 x+20$
Evaluate $105 \times 106$ without multiplying directly.
Find the degree of the polynomials given : $2-y^{2}-y^{3}+2 y^{8}$
Find the value of $k$, if $x -1$ is a factor of $p(x)$ in this case : $p(x)=k x^{2}-3 x+k$