1/x(x+3) + 1/(x+3)(x+6)+...+1/(x+33)(x+36)=3/40

来源：学生作业帮助网编辑：六六作业网时间：2024/12/22 15:58:18

1/x(x+3)+1/(x+3)(x+6)+...+1/(x+33)(x+36)=3/401/x(x+3)+1/(x+3)(x+6)+...+1/(x+33)(x+36)=3/401/x(x+3)+1

1/x(x+3) + 1/(x+3)(x+6)+...+1/(x+33)(x+36)=3/40
1/x(x+3) + 1/(x+3)(x+6)+...+1/(x+33)(x+36)=3/40

1/x(x+3) + 1/(x+3)(x+6)+...+1/(x+33)(x+36)=3/40
1/3*[1/x-1/(x+3)+1/(x+3)-1/(x+6)+……+1/(x+33)-1/(x+36)]=3/40
1/x-1/(x+36)=9/40
36/x(x+36)=9/40
x^2+36x=160
(x-4)(x+40)=0
x=4,x=-40

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