Question

помогите пожалуйста
дам 20б​

Answer 1

$1\dfrac{2}{5}:\dfrac{5}{7}+\dfrac{3}{8}=\dfrac{1\cdot5+2}{5}:\dfrac{5}{7}+\dfrac{3}{8}=\dfrac{7}{5}:\dfrac{5}{7}+\dfrac{3}{8}=\dfrac{7}{5}\cdot\dfrac{7}{5}+\dfrac{3}{8}=\dfrac{7\cdot7}{5\cdot5}+\dfrac{3}{8}=\\\\\\=\dfrac{49}{25}+\dfrac{3}{8}=\dfrac{8\cdot49+25\cdot3}{200}=\dfrac{392+75}{200}=\dfrac{467}{200}=2\dfrac{67}{200}$