Question

By rationalising the denominator of $\frac{1}{3+\sqrt{8}}$, the resulting surd is.......

Answer 1

$\frac{1}{3+\sqrt{8}}=\frac{1}{3+\sqrt{8}}\ast \frac{3-\sqrt{8}}{3-\sqrt{8}}=\frac{3-\sqrt{8}}{9-8}=3-\sqrt{8}$