Mathématiques

Question

svp aider moi important
A= 12/5-3/5×7/9
et
B=(2/3-3):1/9

Merci d'avance

2 Réponse

  • Bonjour Christpvp1

    [tex]A= \dfrac{12}{5}-\dfrac{3}{5}\times\dfrac{7}{9}\\\\A= \dfrac{12}{5}-\dfrac{3\times7}{5\times9}\\\\A= \dfrac{12}{5}-\dfrac{21}{45}\\\\A= \dfrac{12}{5}-\dfrac{7}{15}\\\\A= \dfrac{12\times3}{5\times3}-\dfrac{7}{15}\\\\A= \dfrac{36}{15}-\dfrac{7}{15}[/tex]

    [tex] \\\\\boxed{A= \dfrac{29}{15}}[/tex]


    [tex]B=(\dfrac{2}{3}-3):\dfrac{1}{9}\\\\B=(\dfrac{2}{3}-\dfrac{9}{3}):\dfrac{1}{9}\\\\B=(-\dfrac{7}{3}):\dfrac{1}{9}\\\\B=(-\dfrac{7}{3})\times\dfrac{9}{1}}\\\\B=-\dfrac{63}{3}\\\\\boxed{B=-21}[/tex]
  • A= 12/5-3/5×7/9
     = 12/5 - 21/45
    = 108/45 -21/45
    = 87/45
    = 29*3 / 15*3
    = 29/15

    B=(2/3-3):1/9
    = (2/3-9/3) : 1/9
    = -7/3 x 9
    =  -63/3
    = -21

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