If $x^{3}+3x^{2}+3x=7,$ then $x$ is equal to

$(0.1 \times 0.01 \times 0.001 \times 10^{7})$ is equal to

When simplified,the product $\left(2-\frac{1}{3}\right)\left(2-\frac{3}{5}\right)\left(2-\frac{5}{7}\right) \ldots \left(2-\frac{999}{1001}\right)$ is equal to

$A$ printer numbers the pages of a book starting with $1$ and uses $3189$ digits in all. How many pages does the book have?

If $\left(\frac{x}{y}\right)^{5a-3} = \left(\frac{y}{x}\right)^{17-3a}$,what is the value of $a$?

What approximate value will come in place of the question mark $(?)$ in the given equation? (You are not expected to calculate the exact value)
$2775 \times \frac{160}{\sqrt{?}} = 5550$