Question

1/x(x-1)+1/x(x+1)+1/(x+1)(x+20.+1/(x+9)(x+10)=11/12

Answer 1

原式=1/[x-1]-1/x+1/x-1/[x+1]+1/[x+1]-1/[x+2]+...+1/[x+9]-1/[x+10]=11/12

1/[x-1]-1/[x+10]=11/12

11/[x-1][x+10]=11/12

[x-1][x+10]=12

x=2或x= -11