Tính giá trị biều thức left(frac10+2

Ta có: !!$\left(\frac{10+2 \sqrt{10}}{\sqrt{5}+\sqrt{2}}+\frac{\sqrt{30}-\sqrt{6}}{\sqrt{5}-\sqrt{1}}\right): \frac{1}{2 \sqrt{5}-\sqrt{6}}$ !!$=\left(\frac{\sqrt{100}-\sqrt{40}}{\sqrt{5}+\sqrt{2}}+\frac{\sqrt{5} \cdot \sqrt{6}-\sqrt{5}}{\sqrt{5}-1}\right): \frac{1}{2 \sqrt{5}-\sqrt{6}}$ !!$=\left(\frac{\sqrt{20}(\sqrt{5}+\sqrt{2})}{\sqrt{5}+\sqrt{2}}+\frac{\sqrt{6}(\sqrt{5}-1)}{\sqrt{5}-1}\right) : \frac{1}{2 \sqrt{5}-\sqrt{6}}$ !!$=(2 \sqrt{5}+\sqrt{6})(2 \sqrt{5}-\sqrt{6})$ !!$=(2 \sqrt{5})^{2}-(\sqrt{6})^{2}=20-6=14$