Question

$\sqrt63-\sqrt175+\sqrt28$

Answer 1

$\sqrt{63} - \sqrt{175} + \sqrt{28} \\ = \sqrt{7 \times 9} - \sqrt{7 \times 15} + \sqrt{7 \times 4} \\ = \sqrt{7} ( \sqrt{9} - \sqrt{15} + \sqrt{4} ) \\ = \sqrt{7} (3 - \sqrt{15} + 2) \\ = \sqrt{7} (5 - \sqrt{15} ) \\ = \sqrt{7} ( \sqrt{5 \times 5} - \sqrt{3 \times 5} ) \\ = \sqrt{7} ( \sqrt{5} ( \sqrt{5} - \sqrt{3} )) \\ = \sqrt{35} ( \sqrt{5} - \sqrt{3} )$