Решение:
$$\left(\frac{6}{5} - \frac{3}{4}\right) \cdot \frac{2}{3} = \left(\frac{6 \cdot 4}{5 \cdot 4} - \frac{3 \cdot 5}{4 \cdot 5}\right) \cdot \frac{2}{3} = \left(\frac{24}{20} - \frac{15}{20}\right) \cdot \frac{2}{3} = \frac{9}{20} \cdot \frac{2}{3} = \frac{9 \cdot 2}{20 \cdot 3} = \frac{18}{60} = \frac{3}{10}$$Ответ:
$$\frac{3}{10}$$