2/3 : 2/7 - 1/2х = 2,8 : 4,2 - 9,6х
-0,5х + 9,6х = 28/10 : 42/10 - 2/3 : 2/7
9,1х = 28/10 * 10/42 - 2/3 * 7/2
9,1х = 2/3 - 7/3 = - 5/3
х = - 5/3 : 91/10 = - 5/3 * 10/91
х = - 50/273
2/3 : 2/7 - 1/2х = 2,8 : 4,2 - 9,6х
-0,5х + 9,6х = 28/10 : 42/10 - 2/3 : 2/7
9,1х = 28/10 * 10/42 - 2/3 * 7/2
9,1х = 2/3 - 7/3 = - 5/3
х = - 5/3 : 91/10 = - 5/3 * 10/91
х = - 50/273