Question

1/root3+root7 - 1/root3-root7

Answer 1

$\frac{1}{ \sqrt{3} + \sqrt{7} } - \frac{1}{ \sqrt{3} - \sqrt{7} } \\ \\ = \frac{ (\sqrt{3} - \sqrt{7}) - ( \sqrt{3} + \sqrt{7} )}{( { \sqrt{3} })^{2} - ( { \sqrt{7} })^{2} } \\ \\ = \frac{ - 2 \sqrt{7} }{ - 4} \\ \\ = \frac{ \sqrt{7} }{2}$