Question 24059
<p>Sorry, about the slightly messy notation, but I'm still trying to figure out how to use this thing.</p>

<p>Ok, I assume the thing that's making it tricky for you is the rather nastly looking {{{lg[x]}}}. When I first saw this problem I thought eugh! What on earth am I going to do with that. I then remembered somebody's (probably not) famous theorem.</p>

<p>Logs of different bases differ by a multiplicitive constant!</p>

<p>Let me demonstrate this with an example, say we wanted to solve {{{14^x=29.6}}}. I'm sure you could tell me straight away that the answer is {{{x=lg[14](29.6)}}}. But let's try and work out the answer another way. Lets take {{{lg[10]}}} of both sides of the equation.</p>

{{{lg[10](14^x)=lg[10](29.6)}}}

<p>Applying one of the many "laws of logs"</p>

{{{x*lg[10](14)=lg[10](29.6)}}}

<p>And finally dividing<p>

{{{x=lg[10](29.6)/lg[10](14)}}}

<p>So, we've solved for {{{x}}} in two different ways, and thus we have worked out that</p>

{{{lg[14](29.6)=lg[10](29.6)/lg[10](14)}}}

<p>Now if you can do the same thing and turn the nasty {{{lg[x]}}} into a much nicer {{{lg[3]}}} you should be able to do the problem.</p>

<p>There is another possibly tricky bit, but see how you get on. please write back if you didn't follow that, or you get stuck further on.</p>

<p>Hope that helps</p>

<p>Kev</p>