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

Toán Lớp 8: TÌm x biết x(x+3)(x-3)-3(x+2)(x^2-2x+4)=1-2x^3

Toán Lớp 8: TÌm x biết
x(x+3)(x-3)-3(x+2)(x^2-2x+4)=1-2x^3

Comments ( 2 )

  1. Giải đáp+ Lời giải và giải thích chi tiết:
     x.(x+3).(x-3)-3(x+2).(x^2 -2x +4)=1-2x^3
    =>x. (x^2 −9) −3 .(x^3 +8)−1+2x^3=0

    =>x^3−9x−3x^3−24−1+2x^3=0

    =>(x^3+2x^3−3x^3)−9x−(24+1)=0
    =>−9x−25=0
    =>−9x=25
    =>x=-25/9
    Vậy,x=-25/9

  2. Giải đáp:
     $x.(x+3).(x-3)-3.(x-1).(x²+x+1)=1-2x^3$
    $⇔ x.(x²-9)-3.(x³-1)-1+2x^3=0$
    $⇔ x³-9x-3x³+3-1+2x^3=0$
    $⇔ (x³+2x³-3x³)-9x+(3-1)=0$
    $⇔ -9x+2=0$
    $⇔ -9x=2$
    $⇔ x= \frac{-2}{9}$
    $Vậy$ $x=\frac{-2}{9}$

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