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

Toán Lớp 8: Phân tích đa thức ra nhân tử: 1.$x^{4}$ + $y^{4}$ + $(x + y)^{4}$ 2.$x^{7}$ + $x^{2}$ +1

Toán Lớp 8: Phân tích đa thức ra nhân tử:
1.$x^{4}$ + $y^{4}$ + $(x + y)^{4}$
2.$x^{7}$ + $x^{2}$ +1

Comments ( 1 )

  1. 1, x^4+y^4+(x+y)^4
    =(x^2+y^2)^2-2x^2y^2+(x+y)^4
    =[(x+y)^2-2xy]^2+[(x+y)^2-2xy][(x+y)^2+2xy]
    =[(x+y)^2-2xy][(x+y)^2-2xy+(x+y)^2+2xy]
    =2(x^2+2xy+y^2-2xy)(x+y)^2
    =2(x^2+y^2)(x+y)^2
    2, x^7+x^2+1
    =x^7-x+x^2+x+1
    =x(x^6-1)+(x^2+x+1)
    =x(x^3-1)(x^3+1)+(x^2+x+1)
    =x(x-1)(x^2+x+1)(x^3+1)+(x^2+x+1)
    =(x^2+x+1)[x(x-1)(x^3+1)+1]
    =(x^2+x+1)[(x^2-x)(x^3+1)+1]
    =(x^2+x+1)(x^6+x^2-x^4-x+1)
     

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

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