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

Toán Lớp 8: Thực hiện các phép tính a, (x^3+5x^2-2x+1) (x-7) b, (2x^2-3xy+y^2) (x+y) c, x91-3x) (4-3x) – (x-4) (3x+5)

Toán Lớp 8: Thực hiện các phép tính
a, (x^3+5x^2-2x+1) (x-7)
b, (2x^2-3xy+y^2) (x+y)
c, x91-3x) (4-3x) – (x-4) (3x+5)

Comments ( 2 )

  1. a)(x³+5x²-2x+1)(x-7)
    =x^4-7x^3+5x³-35x²-2x²+14x+x-7
    =x^4-2x^3-37x^2+15x-7
    b)(2x²-3xy+y²)(x+y)
    =2x³+2x²y-3x²y-3xy²+xy²+y³
    =2x³-x²y-2xy²+y³
    c)x(1-3x)(4-3x)-(x-4)(3x+5)
    =(x-3x²)(4-3x)-3x²-5x+12x+20
    =4x-3x²-12x²+9x³-3x²-5x+12x+20
    =9x³-18x²+11x+20
     

  2. a. (x^3+5x^2-2x+1)(x-7)
    =x^4-7x^3+5x^3-35x^2-2x^2+14x+x-7
    =x^4-2x^3-37x^2+15x-7
    b, (2x^2-3xy+y^2)(x+y)
    =2x^3+2x^2y-3x^2y-3xy^2+y^2x+y^3
    =2x^3-x^2y-2xy^2+y^3
    c, Bạn viết lại câu này để mình làm nhé.

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

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