原式=(-47.65)*28/11+37.65*28/11)+10.5*(-82/11) =﹙﹣47.65＋37.65﹚×28/11+10.5*(-82/11)＝﹣280/11﹣11/2×82/11＝－280/11－41＝﹣731/11