(8у - 2)/(1 2/3) = (3у + 1)/(0,8)
(8у - 2) * 0,8 = (3у + 1) * 1 2/3
6,4у - 1,6 = (3 * 5/3)у + 1 2/3
6,4у - 1,6 = 5у + 1 2/3
6,4у - 5у = 1 2/3 + 1,6
1,4у = 5/3 + 16/10 = 50/30 + 48/30 = 98/30 = 3 4/15
у = 3 4/15 : 14/10 = 49/15 * 10/14 = 14/6 = 2 1/3
у = 2 1/3