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

Toán Lớp 8: ( x – 3 ) ^3 – ( x + 2 ) x ( x – 2 ) x ( x – 1 ) ( x + 2y ) ^3 – ( 2x – y ) x ( 4x^2 + 2y + y ^2 )

Toán Lớp 8: ( x – 3 ) ^3 – ( x + 2 ) x ( x – 2 ) x ( x – 1 )
( x + 2y ) ^3 – ( 2x – y ) x ( 4x^2 + 2y + y ^2 )

Comments ( 2 )

  1. Giải đáp+Lời giải và giải thích chi tiết:
     a) (x – 3)³ – (x + 2)(x – 2)(x – 1)
    = (x³ – 9x² + 27x – 27) – (x² – 4)(x – 1)
    = x³ – 9x² + 27x – 27 – x³ + x² + 4x – 4
    = – 8x² + 31x – 31
    b) (x + 2y)³ – (2x – y)(4x² + 2xy + y²)  (Chắc bạn ghi thiếu nên mình sửa lại cho thành HĐT nha)
    = (x³ + 6x²y + 12xy² + 8y³) – (8x³ – y³)
    = x³ + 6x²y + 12xy² + 8y³ – 8x³ + y³
    = – 7x³ + 6x²y + 12xy² + 9y³

  2. #kehuydiet
    (x-3)^3-(x+2)(x-2)(x-1)
    = x^3-9x^2+27x-27-(x^2-4)(x-1)
    = x^3-9x^2+27x-27-x^3+x^2+4x-4
    = -8x^2+31x-31
    ______________________________
    (x+2y)^3-(2x-y)(4x^2+2y+y^2)
    = x^3+6x^2y+12xy^2+8y^3-8x^3+y^3
    = -7x^3+6x^2y+12xy^2+9y^3

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