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

Toán Lớp 6: (3x^2+5).(2x-7)=0 37-7(2x+5)=18

Toán Lớp 6: (3x^2+5).(2x-7)=0
37-7(2x+5)=18

Comments ( 2 )

  1. Giải đáp+Lời giải và giải thích chi tiết:
    (3x^2+5).(2x-7)=0
    <=>$\left[\begin{matrix} 3x^2+5=0\\ 2x-7=0\end{matrix}\right.$
    <=>$\left[\begin{matrix} 3x^2=-5\\ 2x=7\end{matrix}\right.$
    <=>$\left[\begin{matrix} x^2=\dfrac{-5}{3}\\ x=\dfrac{7}{2}\end{matrix}\right.$
    <=>$\left[\begin{matrix} x ∈ ∅\\ x=\dfrac{7}{2}\end{matrix}\right.$
    Vậy x=7/2
    37-7(2x+5)=18
    =>7(2x+5)=37-18
    =>7(2x+5)=19
    =>14x+35=19
    =>14x=19-35
    =>14x=-16
    =>x=-16:14
    =>x=-8/7
    Vậy x=-8/7

  2. Answer
    (3x^{2} + 5) . (2x – 7) = 0
    => $\left[\begin{matrix} 3x^2 + 5 = 0\\ 2x – 7 = 0\end{matrix}\right.$
    => $\left[\begin{matrix} 3x^2 = 0 – 5\\ 2x = 0 + 7\end{matrix}\right.$
    => $\left[\begin{matrix} 3x^2 = – 5\\ 2x = 7\end{matrix}\right.$
    => $\left[\begin{matrix} x^2 = – 5 : 3\\ x = 7 : 2\end{matrix}\right.$
    => $\left[\begin{matrix} x^2 = \dfrac{-5}{3} (loại)\\ x = \dfrac{7}{2} (chọn)\end{matrix}\right.$
    $\text{Vậy}$ x = 7/2
    _______________________
    37 – 7 . (2x + 5) = 18
    => 7 . (2x + 5) = 37 – 18
    => 7 . (2x + 5) = 19
    => 2x + 5 = 19 : 7
    => 2x + 5 = 19/7
    => 2x = 19/7 – 5
    => 2x = -16/7
    => x = -16/7 : 2
    => x = -8/7

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