M-2 4/9+8 13/24+n-3 2/9-4 5/24=m+n-2 4/9-3 2/9+8 13/24-4 5/24=m+n-5 6/9+4 8/24=m+n-5 2/3+4 1/3=m+n-1 1/3;
<span>если m=-3 5/6, n=-2 11/12, то </span>
<span>-3 5/6-2 11/12-1 1/3=-3 10/12-2 11/12-1 4/12=-8 1/12</span>
7.8a + 2.3a - 5a = (7.8 + 2.3 - 5)a = 5.1a
5.1 * 6 = 30.6
2(0.3b + 5) + 1.4b = 2 * 0.3b + 2 * 5 + 1.4b = (0.6 + 1.4)b + 10 = 2b + 10
2 * 4 + 10 = 18
6(a + 1.5) - 2.8a = 6 * a + 6 * 1.5 - 2.8a = (6 - 2.8)a + 9 = 3.2a + 9
3.2 * 1.5 + 9 = 4.8 + 9 = 13.8
4(b + 0.8) + 1.7b = 4b + 4 * 0.8 + 1.7b = (4 + 1.7)b + 3.2 = 5.7b + 3.2
5.7 * 2.3 + 3.2 = 13.11 + 3.2 = 16.31
108:4=27(стр)-в одном журнале.
81:27=3(р)
Ответ:в три раза