Вычислите: \(\frac{3}{\sqrt{5}-\sqrt{2}}+\frac{5}{\sqrt{7}+\sqrt{2}}-\frac{2}{\sqrt{7}-\sqrt{5}}\).

Рационализируем знаменатели:

\[\frac{3}{\sqrt{5}-\sqrt{2}}=\frac{3(\sqrt{5}+\sqrt{2})}{5-2}=\sqrt{5}+\sqrt{2};\]

\[\frac{5}{\sqrt{7}+\sqrt{2}}=\frac{5(\sqrt{7}-\sqrt{2})}{7-2}=\sqrt{7}-\sqrt{2};\]

\[\frac{2}{\sqrt{7}-\sqrt{5}}=\frac{2(\sqrt{7}+\sqrt{5})}{7-5}=\sqrt{7}+\sqrt{5}.\]

Подставим:

\[\left(\sqrt{5}+\sqrt{2}\right)+\left(\sqrt{7}-\sqrt{2}\right)-\left(\sqrt{7}+\sqrt{5}\right)=0.\]

Ответ: 0.