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

Toán Lớp 8: (x-2)*(x^2+3x-1) (x+3)*(2x^2+x-2) (2x-y)*(4x^2-2xy+y^2) mn giúp em vs ạ

Toán Lớp 8: (x-2)*(x^2+3x-1)
(x+3)*(2x^2+x-2)
(2x-y)*(4x^2-2xy+y^2)
mn giúp em vs ạ

Comments ( 2 )

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

  2. \qquad (x-2)(x^2+3x-1)
    =x^3+3x^2-x-2x^2-6x+2
    =x^3+x^2-7x+2
    —————————
    \qquad (x+3)(2x^2+x-2)
    =2x^3+x^2-2x+6x^2+3x-6
    =2x^3+7x^2+x-6
    —————————-
    \qquad(2x-y)(4x^2-2xy+y^2)
    =8x^3-4x^2y+2xy^2-4x^2y+2xy^2-y^3
    =8x^3-8x^2y+4xy^2-y^3
     

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

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