в числители1/6 в знаменатели1/4х-1 1/3 минус 3/8 =1/40

1/6 : (1/4х - 1 1/3) - 3/8 = 1/40
1/4х - 1 1/3 = 1/6 : (1/40 + 3/8)
1/4х - 1 1/3 = 1/6 : (1/40 + 15/40)
1/4х - 1 1/3 = 1/6 : 16/40
1/4х - 1 1/3 = 5/12
1/4х = 5/12 + 1 1/3
1/4х = 5/12 + 4/3
1/4х = 5/12 + 16/12
1/4х  = 31/12
х = 31/12 : 1/4
х = 31/3
х = 10целых 1/3