Rationalise the denominator of the following:

$\frac{1}{\sqrt{7}-2}$

Rationalise the denominator of the following:

Rationalise the denominator of the following:

$\frac{7+3\sqrt{5}}{7-3\sqrt{5}}$

Rationalise the denominator of the following:

$\frac{5-3\sqrt{14}}{7+2\sqrt{14}}$

Rationalise the denominator of the following:

Simplify:

$\frac{\sqrt{6}}{\sqrt{2}+\sqrt{3}}+\frac{3\sqrt{2}}{\sqrt{6}+\sqrt{3}}-\frac{4\sqrt{3}}{\sqrt{6}+\sqrt{2}}$