1.
а) 2/3 * 4/5 = 8/15
б) 3/7 * 7/8 = 3/1 * 1/8 = 3/8
в) 11/12 * 8/9 = 11/3 * 2/9 = 22/27
г) (2/3)^2 = 2/3 * 2/3 = 4/9
д) 2/3 : 5/7 = 2/3 * 7/5 = 14/15
е) 9/16 : 3/2 = 9/16 * 2/3 = 3/8 * 1/1 = 3/8
ж) 3/4 : 4 = 3/4 : 4/1 = 3/4 * 1/4 = 3/16
з) 3 : 3/9 = 3/1 : 3/9 = 3/1 : 9/3 = 27/3 = 9
2.
а) 2 * (12/25 : 6/5) = 0,8
1. 12/25 : 6/5 = 12/25 * 5/6 = 2/5 * 1/1 = 2/5 = 0,4
2. 2 * 0,4 = 2/1 * 4/10 = 1/1 * 4/5 = 4/5 = 0,8
б) 14/15 : 2/3 * 10/21 = 2/3
1. 14/15 : 2/3 = 14/15 * 3/2 = 7/5 * 1/1 = 7/5
2. 7/5 * 10/21 = 1/1 * 2/3 = 2/3
в) 2/3 * 3/4 * 4/5 * 5/6 = (2 * 3 * 4 * 5) : (3 * 4 * 5 * 6) = 120/360 = 1/3
6.2x = 155
155: 6.2
x=25