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

Toán Lớp 8: tính (x+3)(x-1)-(x-7)(x-6) (-x-2)(x+1)-(x-5)(-x+1) (5x(x-3)(x-1)-4x(x^2-2x) ai làm nhanh em cho trlhn ạ

Toán Lớp 8: tính
(x+3)(x-1)-(x-7)(x-6)
(-x-2)(x+1)-(x-5)(-x+1)
(5x(x-3)(x-1)-4x(x^2-2x)
ai làm nhanh em cho trlhn ạ

Comments ( 1 )

  1. 1. (x+3)(x-1)-(x-7)(x-6)
    = (x²+2x-3) -(x²-13x+42)
    = x²+2x-3-x²+13x-42 = 15x-45
    2. (-x-2)(x+1)-(x-5)(-x+1)
    = (-x²-3x-2)-(-x²+6x-5)
    =  -x²-3x-2+x²-6x+5= -9x+3
    3. 5x(x-3)(x-1)-4x(x²-2x)
    = (5x²-15x)(x-1)-(4x³-8x²)
    = (5x³-5x²-15x+15)-(4x³-8x²)
    = 5x³-5x²-15x+15-4x³+8x²
    = x³+3x²-15x+15
     

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