Помогите с логарифмами , срочно нужно на завтра

1) 13*8*log8 (3) = 13*3 = 39
2)
3) log(0,5) (32) = log(1/2) (2^5) = 5*log(1/2) 2 = -5
4) log5 (5) = 1
5) log3 (81)*log6 (216) = log3 (3^4)*log6 (6^3) = 4*3 = 12
6) log6 (54) - log6 (1,5) = log6 (54/1,5) = log6 (54*2/3) = log6 (36) = 2
7) log20 (400) + log(0,05) (20) = log20 (20^2) + log(1/20) (20) = 2 - 1 = 1
8) log(2,75) (4) - log(2,75) (11) = log(2,75) (4/11) = log(11/4) (4/11) = -1
9) log2 (10)/log2 (9) + log9 (0,1) = log9 (10) + log9 (0,1) = log9 (10*0,1) = 0
10) log(0,4) (6)*log6 (2,5) = lg 6/lg(2/5)*lg(5/2)/lg 6 = lg(5/2)/lg (2/5) = -1
11) log7 (5)*log5 (49) = lg 5 / lg 7 * lg 49 / lg 5 = lg(7^2) / lg 7 = 2
12) log3 (0,9) + log3 (10) = log3 (0,9*10) = log3 (9) = 2
13) (1-log3(24))*(1-log9(24)) = (log3(3)-log3(24))(log9(9) - log9 (24)) =
= log3(3/24) * log9(9/24) = log3(1/8) * log9(3/8) = -log3(8) * log9(3/8) =
= -lg 8/lg 3 * lg(3/8) / (2lg 3) = -lg 8*lg(3/8) / (2*(lg 3)^2)
Тут, похоже, какая-то опечатка, потому что это не упрощается.
14) 64*log5 (5^(1/4)) = 64*1/4 = 16
15)
16)
Вторую половину сама, они простые, и мне уже надоело