\[ \cfrac{5\cos^2\left(\cfrac{\pi}{3}\right) + 4\sec^2\left(\cfrac{\pi}{6}\right) - \tan^2\left(\cfrac{\pi}{4}\right)}{\sin^2\left(\cfrac{\pi}{6}\right) + \cos^2\left(\cfrac{\pi}{6}\right)} \] \[ = \cfrac{5\cos^2 60^\circ + 4\sec^2 30^\circ - \tan^2 45^\circ}{\sin^2 30^\circ + \cos^2 30^\circ} \] \[ = \cfrac{5\left(\cfrac{1}{2}\right)^2 + 4\left(\cfrac{2}{\sqrt{3}}\right)^2 - (1)^2}{\left(\cfrac{1}{2}\right)^2 + \left(\cfrac{\sqrt{3}}{2}\right)^2} \] \[ = \cfrac{5 \times \cfrac{1}{4} + 4 \times \cfrac{4}{3} - 1}{\cfrac{1}{4} + \cfrac{3}{4}} \] \[ = \cfrac{\cfrac{5}{4} + \cfrac{16}{3} - 1}{\cfrac{1 + 3}{4}} \] \[ = \cfrac{\cfrac{15 + 64 - 12}{12}}{1} \] \[ = \cfrac{67}{12} \] \[ = 5\cfrac{7}{12} \quad \text{(Answer)} \]