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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 7: -1 va 5/7 .15 + 2/7 .(-15) + (-105) .(2/3 – 4/5 + 1/7 )

Toán Lớp 7: -1 va 5/7 .15 + 2/7 .(-15) + (-105) .(2/3 – 4/5 + 1/7 )

Comments ( 2 )

  1. -1 5/7 . 15 + 2/7 . (-15) + (-105) . ( 2/3 – 4/5 + 1/7)
    =-12/7 . 15 + (-2)/7 . 15 + (-105) . ( 70/105 – 84/105 + 15/105)
    =-12/7 . 15 + (-2)/7 . 15 + (-105) . 1/105
    = (-12/7 + (-2)/7) . 15 + (-1)
    = -2 . 15 + (-1)
    = -30 + (-1)
    = -31
    #caty09

  2. Giải đáp:
    $-31$
    Lời giải và giải thích chi tiết:
    $-1\dfrac57\cdot15+\dfrac27\cdot(-15)+(-105).\left(\dfrac23-\dfrac45+\dfrac17\right)\\=\dfrac{-12}{7}\cdot15+\dfrac{-30}{7}-105\cdot\dfrac{1}{105}\\=\dfrac{-180}{7}+\dfrac{-30}{7}-1\\=-30-1\\=-31$

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222-9+11+12:2*14+14 = ? ( )