ответ:

[tex]\displaystyle \frac{123}{7}=17\frac{4}{7}[/tex]

решение:

[tex]\displaystyle (2\frac{1}{2}+1\frac{1}{3}):\frac{1}{6}-5\frac{3}{7}=\frac{123}{7}=17\frac{4}{7}\\ \\1)((2+1)+(\frac{1}{2}+\frac{1}{3})):\frac{1}{6}-5\frac{3}{7}=((2+1)+(\frac{1}{2}+\frac{1}{3}))*6-5\frac{3}{7}=\\\\((2+1)+(\frac{1}{2}+\frac{1}{3}))*6-\frac{38}{7}\\ \\2)(3+(\frac{1}{2}+\frac{1}{3}))*6-\frac{38}{7}=(3+\frac{5}{6})*6-\frac{38}{7}\\ \\3)3\frac{5}{6}*6-\frac{38}{7}=\frac{23}{6}*6-\frac{38}{7}=23-\frac{38}{7}=\frac{123}{7}=17\frac{4}{7}[/tex]