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

Toán Lớp 8: rút gọn biểu thức: B= (x+1)^3-4x(x+1)(x-1)+3(x-1)(x^2+x+1) giúp ạ!

Toán Lớp 8: rút gọn biểu thức:
B= (x+1)^3-4x(x+1)(x-1)+3(x-1)(x^2+x+1)
giúp ạ!

Comments ( 2 )

  1. B=(x-1)^3-4x(x+1)(x-1)+3(x-1)(x^2+x+1)
    =(x^3-3x^2+3x-1)-4x(x^2-1)+3(x^3-1)
    =x^3-3x^2+3x-1-4x^3+4x+3x^3-3
    =(x^3-3x^3+3x^3)-3x^2+(3x+4x)+(-1-3)
    =-3x^2+7x-4
    $\text{@ThanhTruc2008}$

  2. B= (x-1)^3-4x(x+1)(x-1)+3(x-1)(x^2+x+1)
    ⇔B=(x-1)(x^2+1-2x-4(x+1)+2(x^2+x+1))
    ⇔B=(x-1)(-3x+4)
    ⇔B=-3x^2+7x-4

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