Question

помогите решить логарифм log2(3х-1) = log2(3-х) + log25

Answer 1

$3x-1\ \textgreater \ 0 \ \Rightarrow \ 3x\ \textgreater \ 1 \ \Rightarrow \ x \ \textgreater \ \frac{1}{3} \\ 3-x\ \textgreater \ 0 \ \Rightarrow \ -x\ \textgreater \ -3 \ \Rightarrow \ x\ \textless \ 3 \\ \\ \frac{1}{3} \ \textless \ x \ \textless \ 3 \\ \\ \log_2 (3x-1) -\log_2 (3-x) =\log_2 5 \\ \\ \log_2 (\frac{3x-1}{3-x})=\log_2 5 \\ \\ \frac{3x-1}{3-x}=5 \\ \\ 3x-1=15 -5x \\ \\ 3x+5x=15+1 \\ \\ 8x=16 \\ \\ x=2$