5/7 : (6/7 х +3/7) - 1/2 = 1/6
5/7 : (6/7 х + 3/7) = 1/6 + 1/2
5/7 : (6/7 х + 3/7) = 1/6 + 3/6
5/7 : (6/7 х + 3/7) = 4/6
5/7 : (6/7 х + 3/7) = 2/3
6/7 х + 3/7 = 5/7 : 2/3
6/7 х + 3/7 = 5/7 * 3/2
6/7 х + 3/7 = 15/14
6/7 х = 15/14 - 3/7
6/7 х = 15/14 - 6/14
6/7 х = 9/14
х = 9/14 : 6/7
х = 9/14 * 7/6
х = 3/4 или =0,75