1.
1 1/8 : 3/4 = 9/8 * 4/3 = 3/2 = 1 1/2,
3 3/5 : 2 7/10 = 18/5 * 10/27 = 4/3 = 1 1/3,
4 3/7 :1/7 - 1 5/6 *3 = 31/7 * 7/1 - 6/11 * 3/1 = 31 - 18/11 = 31 - 1 7/11 = 29 4/11,
2.
х = (2 1/2 * 1 4/5) / (3/4) = 5/2 * 9/5 * 4/3 = 3 * 2 = 6 кг,
3.
1/3у + 5/9у = 7,2,
3/9у+5/9у=7,2,
8/9у=7,2,
у=7,2 : 8/9,
у = 7,2 * 9/8,
у = 8,1,
4.
5/6 - х/у = (5у - 6х) / 6у