\(\frac{1}{\sqrt{2}-\sqrt{3}}-\frac{1}{\sqrt{3}-\sqrt{5}}+\frac{1}{\sqrt{5}-\sqrt{7}}\)
= \(-\sqrt{3}-\sqrt{2}+\frac{\sqrt{5}+\sqrt{3}}{2}-\frac{\sqrt{7}+\sqrt{5}}{2}\)
= \(-\sqrt{3}-\sqrt{2}+\frac{\sqrt{3}-\sqrt{7}}{2}\)
= \(\frac{-2\sqrt{3}-2\sqrt{2}+\sqrt{3}-\sqrt{7}}{2}=\frac{-\sqrt{3}-2\sqrt{2}-\sqrt{7}}{2}\)
Chúc bạn học tốt !!!