[tex]Bonjour ; \\\\\\ B = \dfrac{2}{3} - \dfrac{4}{3} \times \dfrac{5}{2} = \dfrac{2}{3} - \dfrac{2\times2}{3} \times \dfrac{5}{2} = \dfrac{2}{3} - \dfrac{2\times2\times 5}{2\times 3} \\\\\\ = \dfrac{2}{3} - \dfrac{2\times 5}{3} = \dfrac{2}{3} - \dfrac{10}{3} = - \dfrac{8}{3} \ .[/tex]
[tex]B= 5 + \dfrac{1+\dfrac{1}{8}}{\dfrac{3}{4}} = 5 + \dfrac{ \dfrac{8}{8} +\dfrac{1}{8}}{\dfrac{3}{4}} = 5 + \dfrac{ \dfrac{9}{8} }{\dfrac{3}{4}} = 5 + \dfrac{9}{8}\times \dfrac{4}{3} \\\\\\ = 5 + \dfrac{3\times3}{2\times4}\times \dfrac{4}{3} = 5 + \dfrac{3\times3\times4}{2\times4\times3} = 5 + \dfrac{3}{2} = \dfrac{10}{2} + \dfrac{3}{2} = \dfrac{13}{2} \ .[/tex]
