очень нужно решить логарифмы

Ответ
a) 5^{3log(5) 20)} = 5^{log(5) 5*20} = 5*20 = 100

б) log(5) 50 - log(5) 2 = log(5) 50/2 = log(5) 25 = log(5) 5^2 = 2

в) log(3) 3,6 - log(3) 1,4 + log(3) {1 2/6} =
= log(3) {3,6/1,4 + 1 2/6} =
= log(3) {36/14 + 8/6} =
= log(3) {18/7 + 4/3} =
= log(3) {(54 + 28)/21} =
= log(3) 3,9 = log(3) {3 * 1,3) = log(3) 3 + log(3) 1,3 = 1 + log(3) 1,3

a) log(4) x < 1/2
log(2^2) x < 1/2
1/2 * log(2) x < 1/2
log(2) x < 1
log(2) x < log(2) 2^0
x < 1

б) log(2) {2,5x + 1} =< -2
log(2) {2x + 1} =< log(2) {2^(-2)}
2x + 1 =< 2^(-2)
2x + 1 =< 1/4
8x + 4 =< 1
8x =< -3
x < -3/8