Question

помогите пожалуйста ​

Answer 1

$(\frac{2}{7}-\frac{7}{17} )*\frac{5}{21} =\frac{2}{7} *\frac{5}{21} -\frac{7}{17} *\frac{5}{21} =\frac{10}{147} -\frac{15}{51} =-\frac{25}{833}$