Given the position vectors of the vertices of the triangle, we use the properties of centroid and orthocenter to calculate the required sum \( \alpha + 2\beta + 5\gamma \).
Final Answer: \( \alpha + 2\beta + 5\gamma = 3 \).
Let $ P_n = \alpha^n + \beta^n $, $ n \in \mathbb{N} $. If $ P_{10} = 123,\ P_9 = 76,\ P_8 = 47 $ and $ P_1 = 1 $, then the quadratic equation having roots $ \alpha $ and $ \frac{1}{\beta} $ is: