Question

[Nguyễn Đức Hiếu]

(√15 - √20) / (10 - √75)

Giải giúp mình nhé mn :)
thx mn nhìu :)

Answer 1

[Dora]

\(\dfrac{\sqrt{15}-\sqrt{20}}{10-\sqrt{75}}\)

\(=\dfrac{\sqrt{15}-2\sqrt{5}}{10-5\sqrt{3}}\)

\(=\dfrac{\sqrt{5}(\sqrt{3}-2)}{-5(\sqrt{3}-2)}\)

\(=\dfrac{-\sqrt{5}}{5}\)

Answer 2

[Roses are roses]

\(=\dfrac{\sqrt{15}-2\sqrt{5}}{10-5\sqrt{3}}=\dfrac{\sqrt{5}\left(\sqrt{3}-2\right)}{5\left(2-\sqrt{3}\right)}=\dfrac{-\sqrt{5}\left(2-\sqrt{3}\right)}{5\left(2-\sqrt{3}\right)}=\dfrac{-\sqrt{5}}{5}=-\dfrac{1}{\sqrt{5}}\)