1/x（x+1）+1/(x+1)（x+2）+1/(x+2)（x+3）+1/(x+3)（x+4）+1/(x+4)（x+5）=5/（x的平方+11x-708）
1/x - 1/(x+1) +1/(x+1) - 1/(x+2) +1/(x+2) - 1/(x+3)+1/(x+3) - 1/(x+4)+1/(x+4)-1/(x+5)=5/(x^2+11x-708)
1/x-1/(x+5)= 5/(x^2+11x-708)
5/[x(x+5)]=5/(x^2+11x-708)
x^2+5x=x^2+11x-708 6x=708 x=118