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

Toán Lớp 8: a 4x ² -4xy + y ² b 9x ³ – 9x ²y – 4x + 4y c x ³ + 2 +3 (x ³ – 2) giúp em nhé cảm ơn ạ

Toán Lớp 8: a 4x ² -4xy + y ²
b 9x ³ – 9x ²y – 4x + 4y
c x ³ + 2 +3 (x ³ – 2)
giúp em nhé cảm ơn ạ

Comments ( 2 )

  1. 4x² -4xy + y²
    =(2x)^2-2.2xy+y^2
    =(2x-y)^2
    9x³ – 9x²y – 4x + 4y
    =9x^2(x-y)-4(x-y)
    =(x-y)(9x^2-4)
    =(x-y)(3x-2)(3x+2)
    x³ + 2 +3 (x³ – 2)
    =x^3+2+3x^3-6
    =4x^3-4
    =4(x^3-1)
    =4(x-1)(x^2+x+1)
    Áp dụng:
    (a-b)^2=a^2-2ab+b^2
    a^2-b^2=(a-b)(a+b)
    a^3-b^3=(a-b)(a^2+ab+b^2)

  2. Giải đáp:
    a, 4x ² -4xy + y ²
    = ( 2x – y)^2
    $\\$
    b, 9x ³ – 9x ²y – 4x + 4y
    = 9x^2( x – y) – 4( x -y)
    = ( 9x^2 – 4)( x – y)
    = ( 3x -2)( 3x +2)( x – y)
    $\\$
    c, x ³ + 2 +3 (x ³ – 2)
    = x^3 + 2 + 3x^3 – 6
    = 4x^3 – 4
    = 4( x -1)( x^2 + x +1)
    Áp dụng :
    1, ( A – B)^2 = A^2 – 2AB + B^2
    2, A^2 – B^2 = ( A – B)( A + B)
    3, A^3 – B^3 = ( A – B)( A^2 + AB + B^2)

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

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