Question

Решите:а)5/21+9/14 б)5/21:9/14 в)5/21-9/14*5/18

Answer 1

а) $frac{5}{21} + frac{9}{14} = frac{5*2}{21*2} + frac{9*3}{14*3} = frac{10}{42} + frac{27}{42} = frac{37}{42}$
б) $frac{5}{21} : frac{9}{14} = frac{5}{21} * frac{14}{9} = frac{70}{189} = frac{10}{27}$
в) 1) $frac{9}{14} * frac{5}{18} = frac{45}{252} = frac{5}{28}$
   2)$frac{5}{21} - frac{5}{28} = frac{5*4}{21*4} - frac{5*3}{28*3} = frac{20}{84} - frac{15}{84} = frac{5}{84}$