If $\frac{x}{y} = \frac{3}{4},$ the ratio of $(2x + 3y)$ and $(3y - 2x)$ is

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

If $x=\sqrt[3]{5}+2,$ then the value of $x^{3}-6 x^{2}+12 x-13$ is

If $\frac{\sqrt{5+x}+\sqrt{5-x}}{\sqrt{5+x}-\sqrt{5-x}}=3,$ then what is the value of $x?$

What should come in place of the question mark $(?)$ in the following equation?
$30.01^{2} - 19.98^{2} - ? = 21.81^{2}$

If $x^{2}+y^{2}+z^{2}=xy+yz+zx$ and $x \neq 0$,then the value of $\frac{4x+2y-3z}{2x}$ is