3*(2 1/2х-0.2)-15 1/15=6-(2/3-0.5х)
3*(2 1/2х-0.2) = 6 3/2X - 0,6 = 7 1/2X - 0,6 = 7,5X - 0,6
6-(2/3-0.5X) = 6 - 2/3 - 0.5X = 5 1/3 - 0.5X
7,5X - 0,6 = 5 1/3 - 0,5X
8X = 5 1/3 + 0,6
5 1/3 + 6/10 = 5 1/3 + 3/5 = 5 5/15 + 9/15 = 5 14/15
8X = 5 14/15
X = 5 14/15:8 = 89/15:8=89/120