3х-6-2х-8=6
3х-2х=6+6+8
х=20
4,25= 425% , так 100% - это единица - 1 целое
2 3/4 : (1 1/2 - 2/5) + (3/4 + 5/6) : 3 1/6 = 11/4 : (3/2 - 2/5) + (3/4 + 5/6) : 19/6 = 11/4 : (15/10 - 4/10) + (9/12 + 10/12) : 19/6 = 11/4 : 11/10 + 19/12 : 19/6 = 11/4 * 10/11 + 19/12 * 6/19 = 10/4 - 6/12 = 30/12 - 6/12 = 24/12 = 2
(1+1)×3=6
(6+1)×4=28
(28+1)×5=145
(145+1)×6=876