Giải thích các bước giải:
$a)\sqrt{3}-\sqrt{27}-\dfrac{\sqrt{99}}{\sqrt{11}}$
$=\sqrt{3}-3\sqrt{3}-\sqrt{9}$
$=-2\sqrt{3}-3$
$b)\sqrt{48}-6\sqrt{\dfrac{1}{3}}-\dfrac{2}{\sqrt{3}}$
$=4\sqrt{3}-\dfrac{6\sqrt{3}}{3}-\dfrac{2\sqrt{3}}{3}$
$=4\sqrt{3}-2\sqrt{3}-\dfrac{2\sqrt{3}}{3}$
$=2\sqrt{3}-\dfrac{2\sqrt{3}}{3}$
$=\dfrac{4\sqrt{3}}{3}$
$c)\dfrac{3}{\sqrt{5}-\sqrt{2}}-\dfrac{3}{\sqrt{5}+\sqrt{2}}$
$=\dfrac{3(\sqrt{5}+\sqrt{2})}{5-2}-\dfrac{3(\sqrt{5}-\sqrt{2})}{5-2}$
$=\dfrac{3(\sqrt{5}+\sqrt{2})}{3}-\dfrac{3(\sqrt{5}-\sqrt{2})}{3}$
$=(\sqrt{5}+\sqrt{2})-(\sqrt{5}-\sqrt{2})$
$=\sqrt{5}+\sqrt{2}-\sqrt{5}+\sqrt{2}$
$=2\sqrt{2}$
Học tốt!!!
