\(x-\dfrac{1}{2}=3\dfrac{1}{2}:\dfrac{2}{7}=\dfrac{7}{2}\times\dfrac{7}{2}\\ =>x-\dfrac{1}{2}=\dfrac{49}{4}\\ =>x=\dfrac{49}{4}+\dfrac{1}{2}\\ =>x=\dfrac{51}{4}\)

\(\dfrac{5}{7}+\dfrac{2}{7}:x=\)1

         \(\dfrac{2}{7}:x=1-\) \(\dfrac{5}{7}\)

          \(\dfrac{2}{7}\) : x  = \(\dfrac{2}{7}\)

                x  = \(\dfrac{2}{7}:\dfrac{2}{7}\)

                x = 1

\(3x-\dfrac{5}{3}=x-\dfrac{1}{4}\\ =>3x-x=\dfrac{5}{3}-\dfrac{1}{4}\\ =>2x=\dfrac{17}{12}\\ =>x=\dfrac{17}{24}\)

\(x\cdot\left(-\dfrac{3}{7}\right)=\dfrac{5}{21}\)

\(x=\dfrac{5}{21}:\left(-\dfrac{3}{7}\right)=\dfrac{5}{21}\times\left(-\dfrac{7}{3}\right)\)

\(x=-\dfrac{5}{9}\)

0,(1) = 1/9

0.(01) = 1/99

1,(8) = 17/9

0,27 = 3/11

\(\dfrac{37}{63}\) : 5 + \(\dfrac{37}{63}\) : 14 = \(\dfrac{37}{63}\) x ( 1/5 + 1/14) # \(\dfrac{37}{63}\) : (5 + 14)

\(\dfrac{25}{12}\).0,8  + \(\dfrac{25}{12}\) . 0,5  = \(\dfrac{25}{12}\). ( 0,8 + 0,5)

   0,8 : { 0,2 - 8 .[ \(\dfrac{7}{48}\)+ ( \(\dfrac{5}{24}\) - \(\dfrac{5}{26}\) ) ] }

= 0,8 : { 0,2 - 8.[ \(\dfrac{7}{48}\) -  \(\dfrac{5}{48}\)]}

= 0,8 : { 0,2 - 8. \(\dfrac{2}{48}\)}

= 0,8 : (0,2 - 1/3)

= 0,8 : (-2/15)

= - 0,8 . 15/2

= - 6 

   \([\)( \(\dfrac{3}{5}\) - \(\dfrac{1}{3}\)) .6 - \(\dfrac{1}{3}\)\(]\) .5

=\([\) \(\dfrac{4}{15}\) .6 - \(\dfrac{1}{3}\) \(]\) . 5 

= \([\) \(\dfrac{4}{5}\) .2 - \(\dfrac{1}{3}\) \(]\) . 5

= 8 - \(\dfrac{5}{3}\)

= 19/3

= 12