(1 1/2:х+2 2/5)*1 2/3-1 2/3=2 5/6,
(3/2:х+12/5)*5/3-5/3=17/6,
(3/2:х+12/5)*5/3=17/6-5/3,
3/2:х+12/5=27/6:5/3,
3/2:х=27/10-12/5,
х=3/2 : 3/10,
х=5
вроде так
(1 1/2:х+2 2/5)*1 2/3-1 2/3=2 5/6,
(3/2:х+12/5)*5/3-5/3=17/6,
(3/2:х+12/5)*5/3=17/6-5/3,
3/2:х+12/5=27/6:5/3,
3/2:х=27/10-12/5,
х=3/2 : 3/10,
х=5
вроде так