a)\(\dfrac{5}{4}\)-\((\dfrac{1}{2}\)\()\)\(^2\)                    b)\(\dfrac{2}{3}\).\(\dfrac{-3}{2}\)+\(\dfrac{-7}{2}\).\(\dfrac{2}{3}\)                            c)\((\)\(\dfrac{1}{5}\)+\(\dfrac{4}{13}\)\()\)+\((\)\(\dfrac{-2}{5}\)+\(\dfrac{7}{13}\)\()\)-\((\)\(\dfrac{4}{5}\)-\(\dfrac{2}{13}\)\()\)

                                                                                           =\(\dfrac{1}{5}\)+\(\dfrac{4}{13}\)+\(\dfrac{-2}{5}\)+\(\dfrac{7}{13}\)-\(\dfrac{4}{5}\)-\(\dfrac{2}{13}\)

=\(\dfrac{5}{4}\)-\(\dfrac{1}{4}\)                          =\(\dfrac{2}{3}\).(\(\dfrac{-3}{2}\)+\(\dfrac{-7}{2}\)\()\)                                 =(\(\dfrac{1}{5}\)+\(\dfrac{-2}{5}\)-\(\dfrac{4}{5}\))+(\(\dfrac{4}{13}\)+\(\dfrac{7}{13}\)-\(\dfrac{2}{13}\))

=\(\dfrac{4}{4}\)=1                           =\(\dfrac{2}{3}\).\(\dfrac{-10}{2}\)                                          =\(\dfrac{-5}{5}\)+\(\dfrac{9}{13}\)

                                     =\(\dfrac{-10}{3}\)                                              =(-1)+\(\dfrac{9}{13}\)

                                                                                             =\(\dfrac{-4}{13}\)

a)A=(\(\dfrac{1}{3}\)-\(\dfrac{8}{15}\)-\(\dfrac{1}{7}\))+(\(\dfrac{2}{3}\)+\(\dfrac{-7}{15}\)+\(1\dfrac{1}{7}\))                                  b)B=0,25+\(\dfrac{3}{5}\)-(\(\dfrac{1}{8}\)-\(\dfrac{2}{5}\)+\(1\dfrac{1}{4}\))

      =\(\dfrac{1}{3}\)-\(\dfrac{8}{15}\)-\(\dfrac{1}{7}\)+\(\dfrac{2}{3}\)+\(\dfrac{-7}{15}\)+\(1\dfrac{1}{7}\)                                            =\(\dfrac{1}{4}\)+\(\dfrac{3}{5}\)-(\(\dfrac{1}{8}\)-\(\dfrac{2}{5}\)+\(\dfrac{5}{4}\))

      =\(\dfrac{1}{3}\)-\(\dfrac{8}{15}\)-\(\dfrac{1}{7}\)+\(\dfrac{2}{3}\)+\(\dfrac{-7}{15}\)+\(\dfrac{8}{7}\)                                               =\(\dfrac{1}{4}\)+\(\dfrac{3}{5}\)-\(\dfrac{1}{8}\)+\(\dfrac{2}{5}\)-\(\dfrac{5}{4}\)

      =\(\dfrac{1}{3}\)+\(\dfrac{2}{3}\)-\(\dfrac{1}{7}\)+\(\dfrac{8}{7}\)-\(\dfrac{8}{15}\)+\(\dfrac{-7}{15}\)                                               =(\(\dfrac{1}{4}\)-\(\dfrac{5}{4}\))+(\(\dfrac{3}{5}\)+\(\dfrac{2}{5}\))-\(\dfrac{1}{8}\)

      =1-1-\(\dfrac{1}{15}\)                                                                     =(-1)+1-\(\dfrac{1}{8}\)

      =0-\(\dfrac{1}{15}\)                                                                         =0-\(\dfrac{1}{8}\)

      =\(\dfrac{-1}{15}\)                                                                           =-\(\dfrac{1}{8}\)