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

Toán Lớp 7: thu gọn tìm bậc: a) (-3xy ³) ³ ×(-2/3x^4y) b) -2/3xy ² – 2xy+4x ²y+12+2_xy ² – 3xy – 20 – 4x ²y

Toán Lớp 7: thu gọn tìm bậc:
a) (-3xy ³) ³ ×(-2/3x^4y)
b) -2/3xy ² – 2xy+4x ²y+12+2_xy ² – 3xy – 20 – 4x ²y

Comments ( 2 )

  1. Giải đáp:
    $\\$
    a,
    (-3 xy^3)^3 . (-2/3 x^4y)
    = -27 x^3 y^9 . (-2)/3 x^4y
    = [(-27) . (-2/3)] (x^3 . x^4) (y^9 . y)
    = 18 x^7 y^{10}
    Bậc : 7 + 10 = 17
    Vậy Bậc của đa thức là : 17
    $\\$
    b,
    (-2)/3 xy^2 – 2xy + 4x^2y +12 + 2xy^2 – 3xy -20 – 4x^2y
    = ( (-2)/3xy^2 + 2xy^2) + (-2xy – 3xy) + (4x^2y-4x^2y) + (12 – 20)
    = 4/3 xy^2 – 5xy- 8
    Bậc : 3
    Vậy Bậc của đa thức là : 3
     

  2. a) (-3xy^3)^3 . ( -2/3 x^4y)
    = (-3)^3 x^3 (y^3)^3 . (-2/3) x^4y
    = [ -27 . (-2/3)] . (x^3 x^4) .( y^9 y)
    = 18 x^7 y^10
    Bậc: 17
    b) -2/3 xy^2 – 2xy + 4x^2y + 12 + 2xy^2 – 3xy – 20 – 4x^2y
    = (-2/3 xy^2 + 2 xy^2) – (2xy + 3xy) + (4x^2y – 4x^2y) + (12 -20)
    =4/3 xy^2 – 5xy -8
    Bậc: 3
     

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