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

Toán Lớp 8: Rút gọn biểu thức: a, A= (2x+3)^2+(4x^2-6x+9)-2(4x^3-1) b, B= (x+1)^3-4x(x+1)(x-1)+3(x-1)(x^2+x+1) giúp nhé

Toán Lớp 8: Rút gọn biểu thức:
a, A= (2x+3)^2+(4x^2-6x+9)-2(4x^3-1)
b, B= (x+1)^3-4x(x+1)(x-1)+3(x-1)(x^2+x+1)
giúp nhé

Comments ( 2 )

  1. #AkaShi
    A=(2x+3)^2+(4x^2-6x+9)-2(4x^3-1)
    A=(2x)^2+2*2x*3+3^3+4x^2-6x+9-8x^3+2
    A=4x²+12x+9+4x^2-6x+9-8x^3+2
    A=(4x^2+4x^2)+(-8x^3)+(12x-6x)+(9+9+2)
    A=8x^2-8x^3-6x+20
    \text{__________________________________________________________________}
    B=(x+1)^2-4x(x+1)(x-1)+3(x-1)(x^2+x+1)
    B=(x³+3x^2+3x+1)-4x(x^2-1)+3(x^3-1)
    B=x³+3x²+3x+1-4x^3+4x+3x^3-3
    B=(x^3+3x^3-4x^3)+3x^2+(3x+4x)+(1-3)
    B=0+3x^2+7x-2
    B=3x^2+7x-2
    \text{__________________________________________________________________}

  2. Giải đáp+Lời giải và giải thích chi tiết:
     A=(2x+3)^2+(4x^2-6x+9)-2(4x^3-1)
       =4x^2+12x+9+4x^2-6x+9-8x^3+2
       =-8x^3+8x^2-6x+20
    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
      =3x^2+7x-2

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