Réponse :
Bonjour,
Exercice 69
a) [tex]\frac{3-\frac{2}{3} }{\frac{4}{3} *7 } = \frac{\frac{9}{3} -\frac{2}{3} }{\frac{28}{3} } = \frac{\frac{7}{3} }{\frac{28}{3} } = \frac{7}{28} = \frac{1}{4}[/tex]
b) [tex]\frac{\frac{2}{3} }{\frac{5}{6} } - \frac{2}{5} = \frac{2}{3} *\frac{6}{5} - \frac{2}{5} = 2*\frac{2}{5} - \frac{2}{5} = \frac{4}{5} - \frac{2}{5} = \frac{2}{5}[/tex]
c) [tex]\frac{-\frac{3}{4}+\frac{1}{2}}{\frac{2}{5} - \frac{5}{2} } = \frac{-\frac{3}{4} + \frac{2}{4} }{\frac{4}{10} - \frac{25}{10} } = \frac{-\frac{1}{4} }{-\frac{21}{10} } = -\frac{1}{4} * (-\frac{10}{21} ) = \frac{10}{84} = \frac{5}{42}[/tex]
Exercice 70
a) [tex]\frac{10}{3} + \frac{8}{9} = \frac{90}{27} + \frac{24}{27} = \frac{114}{27} = \frac{38}{9}[/tex]
b) [tex]\frac{2}{5} * \frac{4}{7} = \frac{8}{35}[/tex]
c) [tex]\frac{3}{2} + \frac{3}{4} * \frac{7}{3} = \frac{3}{2} + \frac{7}{4} = \frac{6}{4} + \frac{7}{4} = \frac{13}{4}[/tex]
d) [tex]\frac{5}{4} * ( \frac{4}{3} - \frac{7}{15} ) = \frac{5}{4} * ( \frac{60}{45} - \frac{21}{45} )= \frac{5}{4} * \frac{39}{45} = \frac{195}{180} = \frac{13}{12}[/tex]
e) [tex]\frac{\frac{1}{2} }{\frac{3}{4}+\frac{1}{6} } = \frac{\frac{1}{2} }{\frac{18}{24} + \frac{4}{24}} = \frac{\frac{1}{2} }{\frac{22}{24} } = \frac{1}{2} * \frac{24}{22} = \frac{24}{44} = \frac{6}{11}[/tex]
