1. \( \frac{1}{5.8} + \frac{1}{8.11} + \frac{1}{11.14} + \ldots + \frac{1}{x.(x+3)} = \frac{101}{1540} \) 2. \( \frac{89}{30} \) 3. 3

----- Nội dung ảnh -----
1. \( \frac{1}{5.8} + \frac{1}{8.11} + \frac{1}{11.14} + \ldots + \frac{1}{x.(x+3)} = \frac{101}{1540} \)

2. \( \frac{89}{30} \)

3. 3