Question

помогите!!!!!!!!!!!!!!! ПЛИС!

Answer 1

2)$frac{5}{21} + frac{4}{21} = frac{9}{21} . frac{21}{21} ,frac{21}{21} - frac{9}{21} = frac{12}{21}$
1) n=$1: frac{2}{7} = frac{7}{7} : frac{2}{7} = frac{7}{7} * frac{7}{2} = frac{49}{14}$

$frac{23}{56} = frac{1}{2}$
K= 1-$frac{1}{2} = frac{1}{2}$