Question

Answer 1

\(\dfrac{1}{\sqrt{7}-2\sqrt{10}}=\dfrac{\sqrt{7}+2\sqrt{10}}{7-40}=-\dfrac{\sqrt{7}+2\sqrt{10}}{33}\)

Answer 2

\(\dfrac{1}{\sqrt{7}-2\sqrt{10}}=\dfrac{-2\sqrt{10}-\sqrt{7}}{33}\)

Answer 3

\(\dfrac{1}{\sqrt{7}-2\sqrt{10}}=\dfrac{\sqrt{7}+2\sqrt{10}}{7-40}\)=\(\dfrac{\sqrt{7}+2\sqrt{10}}{-33}\)

Answer 4

Ai làm đúng vậy ạ