Question

помогите решить под буквой- б

Answer 1

$2 \frac{5}{21} -4 \frac{1}{7} +1 \frac{1}{14} =2-4+1+ \frac{15-6+3}{42} =-1+ \frac{12}{42} =- \frac{30}{42} =- \frac{5}{6}$