15.5×✘=38
15.5×✘=38 -
15.5×✘＝38 x=38/15.5 x=76/31
解：（1+4）x=15.5 5x=15.5 x=3.1
15.5×✘＝38 x=38/15.5 x=76/31
解：（1+4）x=15.5 5x=15.5 x=3.1
9.8×15.5-0.98×5.5 =9.8×15.5-9.8×0.55 =9.8×（15.5-0.55）9.8x14.95 =14.95x（10-0.2）149.5-14.95×0.2 =149.5-0.2×（15-0.05）149.5-3+0.01 =146.51
a,b的值都没有，怎么算，问问题要把全部条件列出，