Пошаговое объяснение:
1)а) 172/316 =43/79
112/80 =7/5 = 1 2/5
2) 5/13 - 3/65= 25/65 - 3/65= 22/65
11/18 + 7/12= 22/36 + 21/36= 43/36= 1 7/36
5/12 - ( 0,125+2/9)= 5/12-(1/8 +2/9)= 5/12- ( 9/72 +16/72)= 5/12- 25/72=
= 30/72 - 25/72= 5/72
3) 5/12 - 1/8 = 10/24- 3/24= 7/24 продали во второй день
5/12 + 7/24= 10/24 + 7/24 = 17/24 печенья продали за два дня
1 - 17/24 = 7/24 осталось не проданной
4) 7/8 = 14/16 > 11/16
8/15 = 32/60 < 7/12= 35/60
5) (х +5/12) * 9/20 = 11/15
(х+5/12) = 11/15 * 20/9
(х + 5/12) = 44/27
х= 44/27 - 5/12
х= 176/108 - 45/108
х= 131/108
х= 1 23/108
