......................................................
25+20=45
45:9=5
25:5=5
20:5=4
одна купила 4 другая 5
(1,8*0,4-2 8/18:6 1/3):(-0,8) = (0.72-2 2/9:6 1/3):(-0,8) =<span>(0.72-20/9:19/3):(-0,8) =
</span>=(0.72-20/9*3/19):(-0,8) =<span>(0.72-60/171):(-0,8) =-0.72/0.8+60/171:0,8=-0,9+75/171=
</span>=-9/10+75/171=-1539/1710+750/1710=-789/1710=-263/570
17(3с+5d)+6c-28d= 51c+85d+6c-28d=57c+57d=57(c+d)⇒ 57*2=114