1/x(x+1)+1/(x+1)(x+2)+.+1/(x+8)(x+9)=(2x+3)/x(x+9)
1/x-1/(x+1)+1/(x+1)1/(x+2)+.+1/(x+8)-1/(x+9)=(2x+3)/x(x+9)
1/x-1/(x+9)=(2x+3)/x(x+9)
(x+9-x)/x(x+9)=(2x+3)/x(x+9)
9/x(x+9)=(2x+3)/x(x+9)
2x+3=9
2x=6
x=3
经检验x=3是方程的解