850-785:5,3=850-148,1132=701,8868
(х+7):8=9 48:(х+3) =6
х+7 = 9×8 х+3=48:3
х+7 = 72 х+3=8
х= 72-7 х=8-3
х = 65 х=5
A) 31/80 +(3/16 + 39/80)= (31/80+39/80)+3/16=70/80+3/16=14/16+3/16=17/16=1 1/16
б) 2/45+(3/45+7/9)=(2/45+3/45)+7/9=5/45+7/9=1/9+7/9=8/9
в) (3/7+ 5/14)+1/14=3/7+(5/14+1/14)=3/7+6/14=3/7+3/7=6/7
С8+9344=24520
с8=24520-9344
с8=15176
с=15176:8=1897.
Ответ: с = 1897.