Question

Вычислите и запишите решение

Answer 1

$\frac{24}{39} \times ( \frac{1}{2} + \frac{7}{12} ) - \frac{8}{9} \div \frac{10}{21} = - 1.2\\ \frac{1}{2} + \frac{7}{12} = \frac{6}{12} + \frac{7}{12} = \frac{6 + 7}{12} = \frac{13}{12} \\ \frac{24}{39} \times \frac{13}{12} = \frac{24 \times 13}{39 \times 12} = \frac{2 \times 1}{3 \times 1} = \frac{2}{3} \\ \frac{8}{9} \div \frac{10}{21} = \frac{8 \times 21}{9 \times 10} = \frac{4 \times 7}{3 \times 5} = \frac{28}{15} \\ \frac{2}{3} - \frac{28}{15} = \frac{10}{15} - \frac{28}{15} = \frac{10 - 28}{15} = - \frac{18}{15} = - \frac{6}{5} = - 1 \frac{1}{5} = - 1.2$