Question

it's answer is -2/3 root 5

Answer 1

yes ir answer is right

Answer 2

$\frac{2 \sqrt{30} }{ \sqrt{6} } - \frac{3 \sqrt{140} }{ \sqrt{28} } + \frac{ \sqrt{55} }{ \sqrt{99} } \\ = \frac{2 \sqrt{30 } }{ \sqrt{6} } \times \frac{ \sqrt{6} }{ \sqrt{6} } - \frac{3 \sqrt{140} }{ \sqrt{28} } \times \frac{ \sqrt{28} }{ \sqrt{28} } + \frac{ \sqrt{55} }{ \sqrt{99} } \times \frac{ \sqrt{99} }{ \sqrt{99} } \\ = \frac{2 \sqrt{180} }{6} - \frac{3 \sqrt{3920} }{28} + \frac{ \sqrt{5445} }{99} \\ = \frac{24 \sqrt{5} }{6} - \frac{84 \sqrt{5} }{28} + \frac{33 \sqrt{5} }{99} \\ = 4\sqrt{5} - 3 \sqrt{5} + \frac{ \sqrt{5} }{3} \\ = \sqrt{5} + \frac{ \sqrt{5} }{3} \\ = \frac{3 \sqrt{5} + \sqrt{5} }{3} \\ = \frac{4 \sqrt{5} }{3}$