Tìm x, biết: \[\left( {\frac{1}{2} + \frac{1}{3} + \frac{1}{4} + ... + \frac{1}} \right) \cdot x = \frac{1} + \frac{2} + \frac{3} + ... + \frac{2} + \frac{1}\].

Tìm x, biết:

\[\left( {\frac{1}{2} + \frac{1}{3} + \frac{1}{4} + ... + \frac{1}} \right) \cdot x = \frac{1} + \frac{2} + \frac{3} + ... + \frac{2} + \frac{1}\].