-17.85x17/6-(-2又13/4)x(3/5-5/3)=-17.85x17/6+(-5/4)x16/25=-17.85x17/6-4/5=-(17+0.85)*(2+5/6)-4/5=-[34+1.7+85/6+4.25/6]-4/5=-[35.7+89.25/6]-4.8/6=-35.7-94.05/6=-35.7-15-4.05/6=-50-0.7-4.05/6=-50-8.25/6...