Exercice 1 le À et le B merci

Bonjour

1 a) [tex]\dfrac{9}{7}-\dfrac{3}{7}\times\dfrac{1}{6}=\dfrac{9}{7}-\dfrac{1}{7}\times\dfrac{1}{2}\\\\=\dfrac{9}{7}-\dfrac{1}{14}\\\\=\dfrac{18}{14}-\dfrac{1}{14}\\\\=\dfrac{17}{14}[/tex]

b) [tex]\dfrac{\dfrac{9}{5}}{\dfrac{3}{4}+\dfrac{3}{5}}=\dfrac{\dfrac{9}{5}}{\dfrac{15}{20}+\dfrac{12}{20}}\\\\\\=\dfrac{\dfrac{9}{5}}{\dfrac{27}{20}}\\\\\\=\dfrac{9}{5}\times \dfrac{20}{27}\\\\=\dfrac{1}{5}\times \dfrac{20}{3}\\\\=\dfrac{1}{1}\times \dfrac{4}{3}\\\\=\dfrac{4}{3}[/tex]