谁能帮个忙要简便运算，求过程

原式=0.8x（2/11+9/11）-4.8x2/7-2.2x7/3 =0.8-（4.9-0.1）x2/7-（2.1+0.1）x7/3 =0.8-1.4+1/35-4.9-7/30 =-11/2+1/35-7/30 =-（11x105-6+49）/210 =-1198/210 =-599/105