Besoin d'aide..s'il vous plaît..

Bonsoir,

[tex]A=(\dfrac{11}{14}+\dfrac{2}{7})\times\dfrac{7}{4}=(\dfrac{11}{14}+\dfrac{4}{14})\times\dfrac{7}{4}=\dfrac{15}{14}\times\dfrac{7}{4}=\dfrac{105}{56}=\dfrac{15\times7}{8\times7}=\dfrac{15}{8}\\\\B=\dfrac{11}{14}+\dfrac{2}{7}\times\dfrac{3}{4}=\dfrac{11}{14}+\dfrac{6}{28}=\dfrac{11}{14}+\dfrac{3}{14}=\dfrac{14}{14}=1\\\\C=\dfrac{9}{4}\times\dfrac{8}{6}+\dfrac{2}{3}\times\dfrac{3}{4}=\dfrac{72}{24}+\dfrac{6}{12}=3+\dfrac{1}{2}=\dfrac{6}{2}+\dfrac{1}{2}=\dfrac{7}{2}[/tex]

[tex]D=\dfrac{9}{4}\times(\dfrac{8}{6}+\dfrac{2}{3})\times\dfrac{3}{4}=\dfrac{9}{4}\times(\dfrac{8}{6}+\dfrac{4}{6})\times\dfrac{3}{4}=\dfrac{9}{4}\times(\dfrac{12}{6})\times\dfrac{3}{4}\\\\=\dfrac{9}{4}\times2\times\dfrac{3}{4}=\dfrac{54}{16}=\dfrac{27}{8}[/tex]