Math Help - Difficult logarithm question - please help?

1. Difficult logarithm question - please help?

If log[a]x=5 and log[a]y=8, solve:

log[a]((ax^2)/(√y))^-2

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I am completely lost. Can someone please give me a step-by-step solution? Please and thank you!

2. Re: Difficult logarithm question - please help?

${\log _a}\left[ {{{\left( {\frac{{a{x^2}}}{{\sqrt y }}} \right)}^{ - 2}}} \right] = - 2\left[ {{{\log }_a}(a) + 2{{\log }_a}(x) - \frac{1}{2}{{\log }_a}(y)} \right]$

3. Re: Difficult logarithm question - please help?

The method given by Plato is good. I was just trying something different. OK