(x-1)(x+1)(x+3)(x+5)+15
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(x-1)(x+1)(x+3)(x+5)+15
(x-1)(x+1)(x+3)(x+5)+15
(x-1)(x+1)(x+3)(x+5)+15
原式=(x^2-1)[(x+3)(x+5)]+15=(x^2-1)(x^2+8x+15)+15=x^2(x^2+8x+15)-(x^2+8x+15)+15=x^4+8x^3+15x^2-x^2-8x-15+15=x^4+8x^3+14x^2-8x
式子当中的x^2为x的平方,其余类推即可.
这个啥问题?看不懂啊
(x-1)(x+1)(x+3)(x+5)+15
=(x^2-1)(x^2+8x+15)+15
=x^4+8x^3+15x^2-x^2-8x^-15+15
=x(x^3+8x^2+14x^-8)
=x(x(x+4)^2-2(x+4))
=x(x+4)(x^2+4x-2)
(x-1)(x+1)(x+3)(x+5)+15
=(x^2-1)(x^2+8x+15)+15
=x^4+8x^3+14x^2-8x
=x(x^3+8x^2+14x-8)
=x[x(x^2+8x+16)-2(x+4)]
=x[x(x+4)^2-2(x+4)]
=x(x+4)(x^2+4x-2) ////如果没有学过无理数，到此为止...
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(x-1)(x+1)(x+3)(x+5)+15
=(x^2-1)(x^2+8x+15)+15
=x^4+8x^3+14x^2-8x
=x(x^3+8x^2+14x-8)
=x[x(x^2+8x+16)-2(x+4)]
=x[x(x+4)^2-2(x+4)]
=x(x+4)(x^2+4x-2) ////如果没有学过无理数，到此为止
=x(x+4)[(x+2)^2-6]
=x(x+4)(x+2+6^0.5)(x+2-6^0.5)
其中，x^2表示x的平方；6^0.5表示根号6
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