原式=1/(x+1)(x+2)+1/(x+2)(x+3)+1/(x+3)(x+4)-1/(x+1)
=1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)+1/(x+3)-1/(x+4)-1/(x+1)
=1/(x+1)-1/(x+1)
=0是解方程。。。。。。没有等号=1，不好意思不对的那个式子就是0额(⊙o⊙)…，那就是无解了，谢谢了