The value of the polynomial $5 x-4 x^{2}+3,$ when $x=-1$ is

Write the following cubes in expanded form

$(2 a-5 b)^{3}$

Without actually calculating the cubes, find the value of each of the following

$(31)^{3}-(16)^{3}-(15)^{3}$

For the polynomial

$\frac{x^{3}+2 x+1}{5}-\frac{7}{2} x^{2}-x^{6},$ write

$(i)$ the degree of the polynomial

$(ii)$ the coefficient of $x^{3}$

$(iii)$ the coefficient of $x^{6}$

$(iv)$ the constant term

Which of the following expressions are polynomials in one variable and which are not $?$ State reason for your answer. If the given expression is a polynomial, state whether it is a polynomial in one variable or not

$x^{2}+2 x y+y^{2}$

Factorise

$16 x^{2}+40 x y+25 y^{2}$