Question

plz help me its urgent

Answer 1

$Given : \frac{15}{\sqrt{10} + \sqrt{20} + \sqrt{40} - \sqrt{5} - \sqrt{80}}$

$= > \frac{15}{\sqrt{10} + 2\sqrt{5} + 2\sqrt{10} - \sqrt{5} - 4\sqrt{5}}$

$= > \frac{15}{3\sqrt{10} - 3\sqrt{5}}$

$= > \frac{15}{3(\sqrt{10} - \sqrt{5})}$

$= > \frac{5}{\sqrt{10} - \sqrt{5}}$

$= > \frac{5}{\sqrt{10} - \sqrt{5}} * \frac{\sqrt{10} + \sqrt{5}}{\sqrt{10} + \sqrt{5}}$

$= > \frac{5(\sqrt{10} + \sqrt{5})}{(\sqrt{10} + \sqrt{5})(\sqrt{10} - \sqrt{5})}$

$= > \frac{5(\sqrt{10} + \sqrt{5})}{10 - 5}$

$= > \frac{5(\sqrt{10} + \sqrt{5})}{5}$

$= > \boxed{\sqrt{10} + \sqrt{5}}}$

Hope this helps!