(一370)x(一0.25)十0.25*24.5+5.5*0.25=370x0.25十0.25*24.5+5.5*0.25=(370+24.5+5.5)*0.25=400*0.25=100
原式＝370*0.25+0.25*24.5+5.5*0.25＝0.25*（370+24.5+5.5）＝0.25*400＝100
原式=0.25x(370+24.5+5.5)=0.25x400=100
