bonjour. aidez moi pour l'exercice 2 svp

Bonjour ;

[tex]B = \dfrac{8 \times10^{11}\times9\times10^{-2}}{12\times(10^4)^2}= \dfrac{8 \times9\times10^{11}\times10^{-2}}{12\times10^{4\times2}} \\\\ = \dfrac{72\times10^{11-2}}{12\times10^8}} = \dfrac{72}{12}\times \dfrac{10^9}{10^8}} = 6 \times 10^{9 - 8} = 6 \times 10^1 = 6 \times 10 = 60 .[/tex]

[tex]A = \dfrac{5}{7} - \dfrac{2}{7} \times \dfrac{4}{3} - \dfrac{5}{3} = \dfrac{5\times3}{7\times3} - \dfrac{2\times4}{7\times3} - \dfrac{5\times7}{3\times7}\\\\ =\dfrac{15}{21}-\dfrac{8}{21}-\dfrac{35}{21} = \dfrac{15-8-35}{21} = \dfrac{-28}{21} = - \dfrac{7 \times 4}{7 \times 3} \\\\ = - \dfrac{4}{3} .[/tex]

Bonjour

A = 5/7 - 2/7 × 4/3 - 5/3
A = 5/7 - (2×4/7×3) - 5/3
A = 15/21 - 8/21 - 35/21
A = -28/21
A = (28÷7)/(21÷7) = - 4/3

B = 8×10^11 × 9×10^-2 / 12×(10^4)^2
B = 8×9 × 10^(11-2) / 12×10^8
B = 72×10^9/12×10^8
B = 72/12 × 10^(9-8)
B = 6×10^1 = 60

Voilà^^