Выразите log4 39.2 через а и б если log7 2=а , log 2 10 =b

[latex]log_4 39,2 = log_4 ( \frac{392}{10}) = log_4 392-log_4 10 = log_4 (49*8)- \frac{1}{2} log_2 10 = [/latex] [latex] = log_4 49+log_4 8 - \frac{1}{2} log_2 10 = log_2 7+ \frac{3}{2} - \frac{1}{2}b = [/latex] [latex] = \frac{1}{log_7 2} + \frac{3}{2} - \frac{1}{2}b = \frac{1}{a} + \frac{3}{2} - \frac{1}{2}b[/latex]