Giải thích các bước giải:
$\dfrac{\sqrt{15}+\sqrt{6}}{\sqrt{35}-\sqrt{14}}$
$=\dfrac{\sqrt{3}(\sqrt{5}+\sqrt{2})}{\sqrt{7}(\sqrt{5}-\sqrt{2})}$
$=\dfrac{\sqrt{3}(\sqrt{5}+\sqrt{2})^2}{\sqrt{7}(\sqrt{5}-\sqrt{2})(\sqrt{5}+\sqrt{2})}$
$=\dfrac{\sqrt{3}(5+2\sqrt{10}+2)}{\sqrt{7}.(5-2)}$
$=\dfrac{5\sqrt{3}+2\sqrt{30}+2\sqrt{3}}{3\sqrt{7}}$
$=\dfrac{7\sqrt{3}+2\sqrt{30}}{3\sqrt{7}}$
$=\dfrac{(7\sqrt{3}+2\sqrt{30}).\sqrt{7}}{3.7}$
$=\dfrac{7\sqrt{21}+2\sqrt{210}}{21}$
Chúc bạn học tốt !!!!
