State whether each of the following statements is true or false

In polynomial $5 x^{3}-3 x^{2}+11 x-14,$ the coefficient of $x^{3}$ is $3.$

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

$\pi x^{2}-\sqrt{3} x+11$

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

$(0.2)^{3}-(0.3)^{3}+(0.1)^{3}$

Find the value of

$x^{3}-8 y^{3}-36 x y-216,$ when $x=2 y+6$

Which of the following expressions is a polynomial, state the reason ? If an expression is polynomial, state whether it is a polynomial in one variable or not

$3 x^{2}+5 x-7+\frac{8}{x}$