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

Toán Lớp 8: Phân tích thành nhân tử: A, x^3-4x^2+12x-27 B, x^2-2x-4y^2-4y C, x^4+2x^3-4x-4 D, ab(a+b)-bc(b+c)+ac(a-c) GIÚP GẤP VỚI MNG ƠI????

Toán Lớp 8: Phân tích thành nhân tử:
A, x^3-4x^2+12x-27
B, x^2-2x-4y^2-4y
C, x^4+2x^3-4x-4
D, ab(a+b)-bc(b+c)+ac(a-c)
GIÚP GẤP VỚI MNG ƠI????

Comments ( 2 )

  1. Giải đáp+Lời giải và giải thích chi tiết:
    a)x^3-4x^2+12x-27
    =x^3-27-4x^2+12x
    =(x-3)(x^2+3x+9)-4x(x-3)
    =(x-3)(x^2+3x-4x+9)
    =(x-3)(x^2-x+9)
    b)x^2-2x-4y^2-4y
    =x^2+4xy+4y^2-2x-4y-4xy-8y^2
    =(x+2y)^2-2(x+2y)-4y(x+2y)
    =(x+2y)(x+2y-2-4y)
    =(x+2y)(x-2y-2)
    c)x^4+2x^3-4x-4
    =x^4+2x^3+2x^2-2x^2-4x-4
    =x^2(x^2+2x+2)-2(x^2+2x+2)
    =(x^2+2x+2)(x^2-2)
    d)ab(a+b)-bc(b+c)+ac(a-c)
    =a^2b+ab^2-bc(b+c)+a^2c-ac^2
    =-bc(b+c)+a^2(b+c)+a(b^2-c^2)
    =-bc(b+c)+a^2(b+c)+a(b-c)(b+c)
    =(b+c)(-bc+a^2+ab-ac)
    =(b+c)[a(a+b)-c(a+b)]
    =(b+c)(a+b)(a-c).

  2. a) x^3-4x^2+12x-27
    =x^3-3x^2-x^2+3x+9x-27
    =x^2(x-3)-x(x-3)+9(x-3)
    =(x-3)(x^2-x+9)
    b) x^2-2x-4y^2-4y
    =(x^2-4y^2)-(2x+4y)
    =(x-2y)(x+2y)-2(x+2y)
    =(x+2y)(x-2y-2)
    c) x^4+2x^3-4x-4
    =x^4-2x^2+2x^3-4x+2x^2-4
    =x^2(x^2-2)+2x(x^2-2)+2(x^2-2)
    =(x^2-2)(x^2+2x+2)
    d) ab(a+b)-bc(b+c)+ac(a-c)
    =b[a(a+b)-c(b+c)]+ac(a-c)
    =b(a^2+ab-bc-c^2)+ac(a-c)
    =b[(a^2-c^2)+b(a-c)]+ac(a-c)
    =b[(a-c)(a+c)+b(a+c)]+ac(a-c)
    =b(a-c)(a+c+b)+ac(a-c)
    =(a-c)[b(a+b+c)+ac]
    =(a-c)(ab+b^2+bc+ac)
    =(a-c)[b(a+b)+c(a+b)]
    =(a+b)(b+c)(a-c)

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

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