Question

rationalise denomator of 1/√7-2

Answer 1

$\frac{1}{ \sqrt{7} - 2} \\ \\ = \frac{1}{ \sqrt{7} - 2 } \times \frac{ \sqrt{7} + 2 }{ \sqrt{7} + 2} \\ \\ = \frac{ \sqrt{7} + 2}{7 - 4} \\ \\ = \frac{ \sqrt{7} + 2 }{3}$