Sagot :
☺ Salut ☺
Effectuons et donnons la réponse sous forme de fraction irréductible :
[tex]A = -\dfrac{5}{8}\times(-\dfrac{6}{5} + \dfrac{- 8}{9})[/tex]
[tex]A = -\dfrac{5}{8}\times(-\dfrac{6}{5} -\dfrac{ 8}{9})[/tex]
[tex]A = -\dfrac{5}{8}\times(\dfrac{- 54 - 40 }{45})[/tex]
[tex]A = -\dfrac{5}{8}\times(- \dfrac{ 94 }{45})[/tex]
[tex]A = \dfrac{5 \times 94}{8\times45}[/tex]
[tex]A = \dfrac{470}{360}[/tex]
✔[tex]\boxed{\boxed{A = \dfrac{47}{36}}}[/tex]✔
____________________
[tex]B = \dfrac{5}{4}-\dfrac{7}{4}\times\dfrac{-8}{5}[/tex]
[tex]B = \dfrac{5}{4}+\dfrac{7 \times8}{4\times5}[/tex]
[tex]B = \dfrac{5}{4}+\dfrac{56}{20}[/tex]
[tex]B = \dfrac{5\times5 + 56}{20}[/tex]
[tex]B = \dfrac{25 + 56}{20}[/tex]
✔[tex]\boxed{\boxed{B = \dfrac{81}{20}}}[/tex]
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[tex]C = \dfrac{4}{7}-\dfrac{2}{7}\times\dfrac{21}{8}[/tex]
[tex]C = \dfrac{4}{7}-\dfrac{2\times21}{7\times8}[/tex]
[tex]C = \dfrac{4}{7}-\dfrac{42}{56}[/tex]
[tex]C = \dfrac{4\times8 - 42}{56}[/tex]
[tex]C = \dfrac{32 - 42}{56}[/tex]
[tex]C = -\dfrac{10}{56}[/tex]
✔[tex]\boxed{\boxed{C = -\dfrac{5}{28}}}[/tex]✔️
____________________
[tex]D = \dfrac{2}{5}\times(1 - \dfrac{1}{4})[/tex]
[tex]D = \dfrac{2}{5}\times(\dfrac{4 - 1}{4})[/tex]
[tex]D = \dfrac{2}{5}\times( \dfrac{3}{4})[/tex]
[tex]D = \dfrac{2\times3}{5\times4}[/tex]
[tex]D = \dfrac{6}{20}[/tex]
✔[tex]\boxed{\boxed{D = \dfrac{3}{10}}}[/tex]✔️
____________________
[tex]E = \dfrac{\dfrac{3}{4} + 3}{\dfrac{1}{2}+2}[/tex]
[tex]E = \dfrac{\dfrac{3 + 12}{4} }{\dfrac{1 + 4}{2}}[/tex]
[tex]E = \dfrac{\dfrac{15}{4}}{\dfrac{5}{2}}[/tex]
[tex]E = \dfrac{15}{4}\times\dfrac{2}{5}[/tex]
[tex]E = \dfrac{15\times2}{4\times5}[/tex]
[tex]E = \dfrac{30}{20}[/tex]
✔[tex]\boxed{\boxed{E = \dfrac{3}{2}}}[/tex]✔️