\(\left(\dfrac{\sqrt{4}-\sqrt{7}}{1-\sqrt{2}}+\dfrac{\sqrt{15}-\sqrt{5}}{1-\sqrt{3}}\right):\dfrac{1}{\sqrt{7}-\sqrt{5}}\\ =\left[\dfrac{\left(2-\sqrt{7}\right)\left(1+\sqrt{2}\right)}{\left(1+\sqrt{2}\right)\left(1-\sqrt{2}\right)}+\dfrac{\sqrt{5}\left(\sqrt{3}-1\right)}{1-\sqrt{3}}\right]:\dfrac{\sqrt{7}+\sqrt{5}}{\left(\sqrt{7}+\sqrt{5}\right)\left(\sqrt{7}-\sqrt{5}\right)}\\ =\left[\dfrac{\left(2-\sqrt{7}\right)\left(1+\sqrt{2}\right)}{1-2}-\dfrac{\sqrt{5}\left(\sqrt{3}-1\right)}{\sqrt{3}-1}\right]:\dfrac{\sqrt{7}+\sqrt{5}}{7-5}\\ =\left[\left(\sqrt{7}-2\right)\left(1+\sqrt{2}\right)-\sqrt{5}\right]:\dfrac{\sqrt{7}+\sqrt{5}}{2}\\ =\left(\sqrt{14}+\sqrt{7}-2-2\sqrt{2}-\sqrt{5}\right)\cdot\dfrac{2}{\sqrt{7}+\sqrt{5}}\)
