Bonjour,
1)a)
[tex]A = \dfrac{8}{3} - \dfrac{7}{2} : \dfrac{14}{8}\\\\ A = \dfrac{8}{3} - \dfrac{7}{2}\times \dfrac{8}{14}\\\\ A = \dfrac{8}{3} - \dfrac{56}{28}\\\\ A = \dfrac{8}{3} - 2\\\\ A = \dfrac{8}{3} - \dfrac{6}{3}\\\\ \boxed{A = \dfrac{2}{3}}[/tex]
[tex]B = \dfrac{2+\dfrac{3}{2}}{\dfrac{5}{6}-\dfrac{2}{3}}\\\\\\ B = \dfrac{\dfrac{4}{2}+\dfrac{3}{2}}{\dfrac{5}{6}-\dfrac{4}{6}}\\\\\\ B = \dfrac{\dfrac{7}{2}}{\dfrac{1}{6}}\\\\\\ B = \dfrac{7}{2}\times 6\\\\ B = \dfrac{42}{2}\\\\ \boxed{B = 21}[/tex]
1)b)
[tex]C = \dfrac{2.10^3\times 48,7\times (10^{-3})^2}{0,5\times 10^4} =\dfrac{2.10^3\times (48,7\times 2)\times (10^{-6\times 2})}{(0,5\times 2)\times 10^4}\\\\C =\dfrac{2.10^3\times 97,4\times 10^{-6}}{10^4}\\\\C =\dfrac{2.10^0\times 97,4\times 10^{-6}}{10^{4-3}}=\dfrac{2\times 97,4\times 10^{-6}}{10^1}\\\\C =\dfrac{2\times 97,4\times 10^{-6}}{10}\\\\C =\dfrac{194,8\times 10^{-6}}{10} = \dfrac{1,948\times 10^{-4}}{10}\\\\C = 1,948 \times 10^{-4}\times \dfrac{1}{10}\\\\C = 1,948 \times 10^{-4}\times 10^{-1}\\\boxed{C = 1,948\times 10^{-5}}= 0,00001948[/tex]
Bonne journée.
