вычислить

Решите задачу:

$\frac{1}{\sqrt{7}+\sqrt{5}}+\frac{4}{\sqrt{5}+2}-\frac{3\sqrt{2.5}+\sqrt{1.5}}{\sqrt{2}}=\\\\ \frac{1*(\sqrt{7}-\sqrt{5})}{(\sqrt{7}+\sqrt{5})*(\sqrt{7}-\sqrt{5})}+\frac{4*(\sqrt{5}-2)} {(\sqrt{5}+2)*(\sqrt{5}-2)}-\frac{(3\sqrt{2.5}+\sqrt{1.5})*\sqrt{2}}{\sqrt{2}*\sqrt{2}}=\\\\ \frac{\sqrt{7}-\sqrt{5}}{(\sqrt{7})^2-(\sqrt{5})^2}+\frac{4*\sqrt{5}-8}{(\sqrt{5})^2-2^2}-\frac{3\sqrt{2.5}*\sqrt{2}+\sqrt{1.5}*\sqrt{2}}{2}=\\\\$

$\frac{\sqrt{7}-\sqrt{5}}{7-5}+\frac{4*\sqrt{5}-8}{5-4}-\frac{3\sqrt{2.5*2}+\sqrt{1.5*2}}{2}=\\\\ \frac{\sqrt{7}-\sqrt{5}}{2}+\frac{4*\sqrt{5}-8}{1}-\frac{3\sqrt{5}+\sqrt{3}}{2}=\\\\ \frac{\sqrt{7}-\sqrt{5}}{2}+\frac{8*\sqrt{5}-16}{2}-\frac{3\sqrt{5}+\sqrt{3}}{2}=\\\\ \frac{\sqrt{7}-\sqrt{5}+8*\sqrt{5}-16-3\sqrt{5}-\sqrt{3}}{2}=\\\\ \frac{\sqrt{7}+4\sqrt{5}-16-\sqrt{3}}{2}$