а) 8/19>х/19, если х=1,2,3,4,5,6,7
б) х/18< 5/6 (5/6 = 15/18), если х=1,2,3,4,5,6,7,8,9,10,11,12,13,14
в)12/23>х/23, если х= 1,2,3,4,5,6,7,8,9,10,11
г) х/36<11/12 (11/12=33/36), если х=1,2,3,4,5,6,7,8,9,10, 11,12,13,14,15,16,17,18, 19,20,21,22,23,24,25,26,27, 28,29,30,31,32