1/X(X+3)+1/(X+3)(X+6)+1/(X+6)(X+9)=3/2X+18 规律是1/X(X+3)=1/X-1

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1/X(X+3)+1/(X+3)(X+6)+1/(X+6)(X+9)=3/2X+18 规律是1/X(X+3)=1/X-1/(X+3)
分母相差几就是几么 ,

∵1/X-1/(X+N)
=(X+N)/[X(X+N)]-X/[X(X+N)]
=N/[X(X+N)]

∴1/[X(X+N)]=1/N[1/X-1/(X+N)]
再问： 1/X(X+3)+1/(X+3)(X+6)+1/(X+6)(X+9)=3/(2X+18) 解出来这个题，100财富给你
再答： ��Ǵ��ģ� 1/X(X+3)+1/(X+3)(X+6)+1/(X+6)(X+9) =1/3[1/X-1/(X+3)+1/(X+3)-1/(X+6)+1/(X+6)-1/(X+9)] =1/3[1/X-1/(X+9)] =1/3*9/[X(X+9)] =3/(X²+9x)
再问： ��ǽⷽ�̣�ͬ־��
再答： ��һ��䡣ֱ��˵�ⷽ�̵��ˣ� ��Ϲ��ɵ�X²+9x=2X+18 ��x²+7X-18=0 ��x1=2�� x2=-9(��⣬��ȥ) ��X=2
再问： ��д��ϸ��ô��ѧϰ��ܺã��̫��̡�
再答： 1/X(X+3)+1/(X+3)(X+6)+1/(X+6)(X+9)=3/(2X+18) 1/3[1/X(X+3)+1/(X+3)(X+6)+1/(X+6)(X+9)]=3/(2X+18) [1/x-1/(x+3)+1/(x+3)-1/(x+6)+1/(x+6)-1/(x+9)]=9/(2x+18) 1/x-1/(x+9)=9/2(x+9) (x+9-x)/x(x+9)=9/2(x+9) 9/x(x+9)=9/2(x+9) ∴x(x+9)=2(x+9) x²+9x-2x-18=0 x²+7x-18=0 ∴x+9=0 x-2=0 x=-9 (不符题意，舍去) ∴x=2 若还有疑问，可在HI里复制提问，免得浪费财富。

|X-1|+|X-2|+|X-3|+|X-4|+|X-5|+|X-6|+|X-7|+|X-8|+|X-9|+|X-10| 解方程x/(x-2)=2x/(x-3)+(1-x)/(x-5x+6) x^5+x^4 = (x^3-x)(x^2+x+1)+x^2+x y=(x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9)(x-10)的导数在x=1 设函数f(x)=(x-1)(x-2)(x-3)(x-4)(x-5)(x-6)(x-7)(x-8)(x-9)(x-10), （1） x-3/x-2 - x-5/x-4=x-7/x-6 - x-9/x-8 2x/x^2-9=x-1/x^2-6x+9-1/x+3 (x-2)(x2-6x-9)-x(x-5)(x-3)其中x= -1/3 1/X(X+3)+1/(X+3)(X+6)+1/(X+6)(X+9)=3/2X+18 规律是1/X(X+3)=1/X-1 x+2/x^2-x-6 + 2x/x^3-3x - x+1/x^2-6x+9 (x+2/x^2-x-6)-(2x/x^2-3x)-(x+1/x^2-6x+9) 已知3x*x-x=1,求6x*x*x+7x*x-5x+2000