$$\frac{(\sqrt{a} + \sqrt{b})^2 - b}{2\sqrt{ab} + 2b + 1} = \frac{a + 2\sqrt{ab} + b - b}{2\sqrt{ab} + 2b + 1} = \frac{a + 2\sqrt{ab}}{2\sqrt{ab} + 2b + 1}$$
Подставим $$a = 5$$ и $$b = 2$$:
$$\frac{5 + 2\sqrt{5 * 2}}{2\sqrt{5 * 2} + 2 * 2 + 1} = \frac{5 + 2\sqrt{10}}{2\sqrt{10} + 4 + 1} = \frac{5 + 2\sqrt{10}}{2\sqrt{10} + 5} = 1$$