Помогите пожалуйста.........

Решите задачу:

$log_{a}b=3\\\\\\log_{\sqrt[4]{ab}}\, \frac{b}{\sqrt{a}} +log_{\sqrt[4]{ab}}\,\sqrt[4]{\frac{a}{b} }=4\cdot log_{ab}\, \frac{b}{\sqrt{a}}+4\cdot \frac{1}{4}\cdot log_{ab}\, \frac{a}{b}=\\\\=4\cdot (log_{ab}\, b-log_{ab}\sqrt{a})+(log_{ab}a-log_{ab}b)=\\\\=4\cdot log_{ab}b-2\cdot log_{ab}a+log_{ab}a-log_{ab}b=\\\\=3\cdot log_{ab}\, b-log_{ab}\, a=3\cdot \frac{log_{a}b}{log_{a}\, ab} -\frac{log_{a}\, a}{log_{a}\, ab} =\\\\=3\cdot \frac{3}{1+log_{a}\, b} - \frac{1}{1+log_{a}\, b} =\frac{9}{1+3} - \frac{1}{1+3}= \frac{9}{4} -\frac{1}{4}= \frac{8}{4}= 2$