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

Toán Lớp 8: phân tích đa hức thành nhân tử a, x^2 – 4x^2y^2+y^2+2xy b, x^6 – y^6 e, (a+b+c)^2 + (a+b – c)^2 – 4c^2

Toán Lớp 8: phân tích đa hức thành nhân tử
a, x^2 – 4x^2y^2+y^2+2xy
b, x^6 – y^6
e, (a+b+c)^2 + (a+b – c)^2 – 4c^2

Comments ( 2 )

  1. Giải đáp:
    a)(x+y+2xy)(x+y-2xy)
    b)(x+y)(x²-xy+y²)(x-y)(x²+xy+y²)
    e)2(a+b+c)(a+b-c)
    Lời giải và giải thích chi tiết:
    a)x²-4x²y²+y²+2xy
    =(x²+2xy+y²)-4x²y²
    =(x+y)²-(2xy)²
    =(x+y+2xy)(x+y-2xy)
    b)x^6-y^6
    =(x^3)^2-(y^3)^2
    =(x³+y³)(x³-y³)
    =(x+y)(x²-xy+y²)(x-y)(x²+xy+y²)
    e)(a+b+c)²+(a+b-c)²-4c²
    =(a+b+c)²+[(a+b-c)²-4c²]
    =(a+b+c)²+[(a+b-c)²-(2c)²]
    =(a+b+c)²+(a+b-c+2c)(a+b-c-2c)
    =(a+b+c)²+(a+b+c)(a+b-3c)
    =(a+b+c)(a+b+c+a+b-3c)
    =(a+b+c)(2a+2b-2c)
    =2(a+b+c)(a+b-c)

  2. a)
    x^2 – 4x^2y^2 + y^2 + 2xy
    = x^2 + 2xy + y^2 – 4x^2y^2
    = (x + y)^2 – (2xy)^2
    = (x + y – 2xy)(x + y + 2xy)
    b)
    x^6 – y^6
    (x^3)^2 – (y^3)^2
    = (x^3 –  y^3)(x^3 + y^3)
    = (x – y)(x^2 + xy + y^2)(x + y)(x^2 – xy + y^2)
    c)
    (a + b + c)^2 + (a + b – c)^2 – 4c^2
    = a^2 + b^2 + c^2 + 2ab + 2bc + 2ca + a^2 + b^2 + c^2 + 2ab – 2bc – 2ca – 4c^2
    = 2a^2 + 2b^2 + 2c^2 + 4ab – 4c^2
    = 2(a^2 + b^2 + c^2 + 2ab – 2c^2)
    = 2(a^2 + b^2 + 2ab – c^2)
    = 2[(a + b)^2 – c^2]
    = 2(a + b + c)(a + b – c)

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