Ответ:

[tex] - 2[/tex]

Объяснение:

[tex]4 \times \frac{2}{3} \div 4 \times \frac{9}{10} - (4 \times \frac{1}{2} - 3 \times \frac{5}{7} \times \frac{5}{12} = \frac{14}{3} \times \frac{10}{49} - ( \frac{9}{2} - \frac{13}{7} \times \frac{5}{6} ) = \frac{2}{3} \times \frac{10}{7} - ( \frac{9}{2} - \frac{65}{42} ) = \frac{20}{21} - \frac{62}{21} = - 2[/tex]