\frac4\sqrt5 - \sqrt3 \cdot \frac\sqrt5 + \sqrt3\sqrt5 + \sqrt3 = \frac4(\sqrt5 + \sqrt3)(\sqrt5)^2 - (\sqrt3)^2 = \frac4(\sqrt5 + \sqrt3)5 - 3 = \frac4(\sqrt5 + \sqrt3)2 = 2(\sqrt5 + \sqrt3). - go-checkin.com