1/x(x+1)+1/(x+1)(x+2)+1/(x+2)(x+3)+...+1/(x+9)(x+10)=5/121/x-1/(x+1)+1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)+...+1/(x+9)-1/(x+10)=5/121/x-1/(x+10)=5/1210/x(x+10)=5/12所以x²+10x-24=0(x+12)(x-2)=0x=-12,x=2...