Пошаговое объяснение:
1.
148 : (8а - 3) + 6 2003
----------------------- = -------- ,
10 2003
148 : (8а - 3) + 6 10
----------------------- = -------- ,
10 10
148 : (8а - 3) + 6 = 10,
148 : (8а - 3) = 10 - 6,
148 : (8а - 3) = 4,
8а - 3 = 148 : 4,
8а - 3 = 37,
8а = 37 + 3,
8а = 40,
а = 5,
проверка:
(148 : (8*5 - 3) + 6 ) / 10 = 2003 / 2003,
(148 : (40 - 3) + 6 ) / 10 = 1,
(148 : 37 + 6 ) / 10 = 1,
(148 : 37 + 6 ) / 10 = 1,
(4 + 6) / 10 = 1,
10 / 10 = 10,1 = 1,
2.
2/3 * 3 = 6/3 = 2,
1/6 * 3 = 3/6 = 1/2,
2/7 * 3 = 6/7,
5/12 * 3 = 15/12 = 5/4 = 1 1/4,
3.
2/4 : 2 = 1/4,
3/8 : 2 = 3/16,
2/5 : 2 = 1/5,
7/9 : 2 = 7/18,
1/2 : 2 = 1/4,
4.
а) х = 199/200, 298/300, 299/300, 397/400, 398/400, 399/400, .....,
б) х = 1/2 (или 5/10), 7/15, 8/15, 9/20, 1/2 (или 10/20), 11/20, .....,
в) х = 5/12, 7/18, 4/9 (или 8/18), .....,
5.
5/7 < х < 6/7,
20/28 < х < 24/28,
х = 21/28,
х = 3/4