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

Toán Lớp 8: A.(y^2x-2xy).(-3x^2y) B.-3/4.x(4x-8) C.(x-1).(x+1).(x+2) D.(5x-2y).(x^2-xy+1)

Home/ Toán Lớp 8: A.(y^2x-2xy).(-3x^2y) B.-3/4.x(4x-8) C.(x-1).(x+1).(x+2) D.(5x-2y).(x^2-xy+1)

Toán Lớp 8: A.(y^2x-2xy).(-3x^2y) B.-3/4.x(4x-8) C.(x-1).(x+1).(x+2) D.(5x-2y).(x^2-xy+1)

Tháng Mười Hai 9, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: A.(y^2x-2xy).(-3x^2y)
B.-3/4.x(4x-8)
C.(x-1).(x+1).(x+2)
D.(5x-2y).(x^2-xy+1)

Comments ( 2 )

  1. maitrucloan
    maitrucloan
    9 Tháng Mười Hai, 2022 at 12:28 sáng
    Reply
    ***Lời giải***
    A)
    (-3x^2y)(y^2x-2xy)
    =-3x^2y.y^2x-3x^2y.-2xy
    =-3x^3y^3+6x^3y^2
    B)
    -3/4.x(4x-8)
    =-3/4.x.4x-3/4.x.-8
    =-3x^2+6x
    C)
    (x-1).(x+1).(x+2)
    =(x^2-1)(x+2)
    =x^2(x+2)-(x+2)
    =x^3+2x^2-x-2
    D)
    (5x-2y).(x^2-xy+1)
    =5x(x^2-xy+1)-2y(x^2-xy+1)
    =5x^3-5x^2y+5x-2x^2y+2xy^2-2y
    =5x^3-7x^2y+5x+2xy^2-2y

  2. truongthanhhung
    truongthanhhung
    9 Tháng Mười Hai, 2022 at 12:27 sáng
    Reply
    Lời giải :
    a,
    (y^2x-2xy).(-3x^2y)
    =y^2x.(-3x^2y)-2xy.(-3x^2y)
    =-3x^3y^3+6x^3y^2
    b,
    -3/4x(4x-8)
    =-3/4x . 4x – 3/4x . (-8) 
    =-3x^2+6x
    c,
    (x-1)(x+1)(x+2)
    =(x^2-1)(x+2)
    =x^3+2x^2-x-2
    d,
    (5x-2y)(x^2-xy+1)
    =5x.x^2+5x.(-xy)+5x.1-2y.x^2-2y.(-xy)-2y.1
    =5x^3-5x^2y+5x-2x^2y+2xy^2-2y
    =5x^3+(-5x^2y-2x^2y)+5x+2xy^2-2y
    =5x^3-7x^2y+5x+2xy^2-2y

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

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