设1/10(x-100)=t,则x-100=10t,x=10t+100100+1/10(x-100)=200+1/10[x-200-100-1/10(x-100)] 100+t=200+1/10[10t-200-t] 1000+10t=2000+10t-200-tt=800x=10t+100=8100