а) x = 1/6 - 2/3
x = 1/6 - 4/6
x = -3/6
x = -1/2

б) 3/4 - 1/2x = 3/8
-1/2x = 3/8 - 3/4
-1/2x = 3/8 - 6/8
-1/2x = -3/8
x = $-3/8$ / $-1/2$ x = -3/8 * -2/1
x = 6/8
x = 3/4

в) 3/10x - 1/5 = 1 7/20
3/10x = 1 7/20 + 1/5
3/10x = 1 7/20 + 4/20
3/10x = 1 11/20
3/10x = 20/20 + 11/20
3/10x = 31/20
x = $31/20$ / $3/10$ x = 31/20 * 10/3
x = 155/60
x = 31/12