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

Toán Lớp 8: Thực hiện phép nhân và chia sau: a) (2x^4y– x^3 + x^2y^3). 5x^2y b) (10x^4 – 5x^3 + 3x^2) : 5x^2 c) (x – 4).(yx + 1) d) (x^3 + 4

Toán Lớp 8: Thực hiện phép nhân và chia sau:
a) (2x^4y– x^3 + x^2y^3). 5x^2y b) (10x^4 – 5x^3 + 3x^2) : 5x^2
c) (x – 4).(yx + 1) d) (x^3 + 4x^2 – x – 4) : (x + 1)
e)(xy^2)^4:(xy^2)^2

Comments ( 1 )

  1. a)
    (2x^4y – x^3 + x^2 y^3) . 5x^2y
    = 5x^2y . 2x^4y – 5x^2y . x^3 + 5x^2y . x^2 y^3
    = 10 x^6 y^2 – 5 x^5 y + 5 x^4 y^4
    b)
    (10x^4 – 5x^3 + 3x^2) : 5x^2
    = 10x^4 : 5x^2 – 5x^3 : 5x^2 + 3x^2 : 5x^2
    = 2 x^2 – x + 3/5
    c)
    (x-4)(yx+1)
    = x . yx + x . 1 – 4 . yx – 4 . 1
    = x^2y + x – 4xy – 4
    d)
    (x^3 + 4x^2 – x – 4) : (x+1)
    = [(x^3 + 3x^2 – 4x) + (x^2 + 3x – 4) ] : (x+1)
    = [ x (x^2 + 3x -4) + (x^2 + 3x-4)] : (x+1)
    =  (x^2 + 3x – 4)(x+1) : (x+1)
    = (x^2 – x + 4x – 4)(x+1) : (x+1)
    = x^2 – x + 4x – 4
    e)
    (xy^2)^4 : (xy^2)^2
    = ( xy ^2)^2
    = x^2 y^4

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