Bài `2` :
`a) \frac{-3}{4}. 31\frac{11}{23} - 0,75.8\frac{12}{23}`
`=\frac{-3}{4}. 31\frac{11}{23} - \frac{3}{4}.8\frac{12}{23}`
`= \frac{-3}{4}.(31\frac{11}{23} - 8\frac{12}{23} )`
`=\frac{-3}{4}. 23\frac{-1}{23} `
`= \frac{-3}{4} . \frac{528}{23} = \frac{-396}{23} `
`b, ( 2\frac{1}{3} + 3\frac{1}{2} ) : ( -4\frac{1}{6} + 3\frac{1}{7} ) + 7\frac{1}{2}`
`= \frac{35}{6} : \frac{-29}{42} + \frac{15}{2}`
`= \frac{245}{29} + \frac{15}{2}`
`= \frac{925}{58}`
`c, 4\frac{5}{9} : ( \frac{-5}{7} ) + 4\frac{5}{9} : ( \frac{-5}{7} )`
`=\frac{41}{9} : ( \frac{-5}{7} + \frac{-5}{7} )`
`= \frac{41}{9} : \frac{-10}{7}`
`=\frac{41}{9} . \frac{-7}{10} = \frac{-287}{90}`
`d, ( \frac{12}{35} - \frac{6}{7} + \frac{18}{14} ) : \frac{6}{-7} - \frac{-2}{5} - 1`
`=(\frac{-18}{35} + \frac{18}{14} ) . \frac{-7}{6} - \frac{-2}{5} - 1`
`= \frac{27}{35} . \frac{-7}{6} - \frac{-2}{5} - 1`
`=\frac{27}{30} - \frac{-2}{5} - 1`
`= \frac{39}{30} - 1`
`= \frac{3}{10}`
`e, 4\frac{25}{16} + 25( \frac{9}{16} : \frac{125}{64} : \frac{-27}{8})`
`=4\frac{25}{16} + 25( \frac{9}{16} . \frac{64}{125} . \frac{-8}{27})`
`=4\frac{25}{16} + 25.\frac{32}{375}`
`= \frac{89}{16} + \frac{32}{15}`
`= \frac{1847}{240}`
`g, \frac{2}{3} - 4(\frac{1}{2} - \frac{3}{4} )`
`= \frac{2}{3} - 4.\frac{1}{8}`
`= \frac{2}{3} - \frac{1}{2}`
`= \frac{1}{6}`
