Question

Помогите решить 1,2,3,4 номер срочно!!!
Спасибо.
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Answer 1

$1) \\ \\ \frac{21}{40} \div \frac{3}{4} = \frac{21}{40} \times \frac{4}{3} = \\ \\ \frac{(21 \times 3) \times (4\times 40)}{120} = \\ \\ \frac{63 \times 160}{120} = \frac{10080}{120} = 84$

$2) \\ 1 \frac{5}{9} \div 1 \frac{8}{27} = \\ \\ \frac{14}{9} \times \frac{27}{35 } \\ \\ = \frac{(14 \times 35) \times (27 \times 9)}{315} = \\ \\ \frac{490 \times 243}{315} = \frac{119070}{315} = 378$

$3) \\ \\ 12 \div \frac{15}{16} = 11 \frac{16}{16} \div \frac{15}{16} = \\ \\ 11 \frac{16}{16} \times \frac{16}{15} = 11 \frac{16}{1} \times \frac{1}{15} = \\ \\ 11 \frac{16}{15} = 12 \frac{1}{15}$

$\frac{9}{17} \div 6 = \frac{9}{17} \div \frac{6}{1} = \frac{9}{17} \times \frac{1}{6} = \\ \\ \frac{3}{17} \times \frac{1}{2} = \frac{3}{34}$