Question

Rationalise the denominator of $\frac{1}{7+4\sqrt{3}}$

Answer 1

$\frac{1}{7+4\sqrt{3}}$

$(7-4\sqrt{3})$

$\frac{1\times (7-4\sqrt{3})}{(7+4\sqrt{3})(7-4\sqrt{3})}$

$=\frac{7-4\sqrt{3}}{(7{)}^2-(4\sqrt{3}{)}^2}$

$=\frac{7-4\sqrt{3}}{49-48}$

$=7-4\sqrt{3}$