初二数学因式分解1.(x^2+4
1。(x^2+4x+8)^2+3x(x^2+4x+8)+2x^2
=[(x^2+4x+8)+x][(x^2+4x+8)+2x]
=(x^2+5x+8)(x^2+6x+8)
=(x^2+5x+8)(x+2)(x+4)
2。 (xy-1)^2+(x+y-2)(x+y-2xy)
=x^2y^2-2xy+1+x^2+xy-2x^2y+xy+y^2-2xy^2-2x-2y+4xy
=(x^2y^2-2x^2y+x^2)+(y^2-2y+1)-(2xy^2-4xy+2x)
=x^2(y^2-2y+1)+(y^2-2y+1)-2x(y^2-2y+1)
=(y^2-2y+1)(x^2+1-2x)
=[(...全部
1。(x^2+4x+8)^2+3x(x^2+4x+8)+2x^2
=[(x^2+4x+8)+x][(x^2+4x+8)+2x]
=(x^2+5x+8)(x^2+6x+8)
=(x^2+5x+8)(x+2)(x+4)
2。
(xy-1)^2+(x+y-2)(x+y-2xy)
=x^2y^2-2xy+1+x^2+xy-2x^2y+xy+y^2-2xy^2-2x-2y+4xy
=(x^2y^2-2x^2y+x^2)+(y^2-2y+1)-(2xy^2-4xy+2x)
=x^2(y^2-2y+1)+(y^2-2y+1)-2x(y^2-2y+1)
=(y^2-2y+1)(x^2+1-2x)
=[(y-1)^2][(x-1)^2]
3。
6x^4+5x^3-38x^2+5x+6
=(6x^4+5x^3-39x^2)+(x^2+5x+6)
=x^2(6x^2+5x-39)+(x+2)(x+3)
=x^2(x+3)(6x-13)+(x+2)(x+3)
=(x+3)(6x^3-13x^2+x+2)
=(x+3)(6x^3-13x^2+2x-x+2)
=(x+3)[x(6x^2-13x+2)-(x-2)]
=(x+3)[x(x-2)(6x-1)-(x-2)]
=(x+3)[(x-2)(6x^2-x-1)]
=(x+3)[(x-2)(2x-1)(3x+1)
。
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