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

Toán Lớp 8: (x-2)(4x+1)-4x(x+7)=1 giải hộ e

Toán Lớp 8: (x-2)(4x+1)-4x(x+7)=1
giải hộ e

Comments ( 2 )

  1. Answer
    (x – 2) . (4x + 1) – 4x . (x + 7) = 1
    => x . 4x + x . 1 – 2 . 4x – 2 . 1 – 4x . x – 4x . 7 = 1
    => 4x^2 + x – 8x – 2 – 4x^2 – 28x = 1
    => (4x^2 – 4x^2) + (x – 8x – 28x) – 2 = 1
    => -7x – 28x – 2 = 1
    => -35x – 2 = 1
    => -35x = 1 + 2
    => -35x = 3
    => x= 3 : (-35)
    => x = {-3}/35
    $\text{Vậy}$ x = -3/35

  2. (x-2)(4x+1)-4x(x+7)=1
    =>4x²+x-8x-2-4x²-28x=1
    =>(4x²-4x²)+(x-8x-28x)-2=1
    =>0+(-35)x-2=1
    =>(-35)x-2=1
    =>(-35)x=1+2
    =>(-35)x=3
    =>x=-3/35
    Vậy x=-3/35

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