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giant_bob · Jul 18, 2007, 02:40 AM

Hello,
After many pages of working, I've managed to work my way to an equation that looks like this:

x=10ln(y/(5-15y))-26

I now need to rearrange this equation to y=...
No matter how many times I try I just can't seem to get it.
I'm farily sure that the above equation is correct but the fact that I can't seem to rearrange it means I may have to go back to the beginning.
I thought I might plead for some help from someone smarter than myself before I damage some poor wall with my head...

galactus · Jul 18, 2007, 04:50 AM

$x=10ln(\frac{y}{5-15y})-26$

$\frac{x+26}{10}=ln(\frac{y}{5-15y})$

$e^{\frac{x+26}{10}}=\frac{y}{5(1-3y)}$

$5e^{\frac{x+26}{10}}=\frac{y}{1-3y}$

reciprocals will help:

$\frac{1}{5}e^{-(\frac{x+26}{10})}=\frac{1-3y}{y}=\frac{1}{y}-3$

Now, can you finish? I don't want to spoil the ending.:)

giant_bob · Jul 18, 2007, 03:45 PM

You sir, are my new hero

I can't believe I didn't think to flip the equation to cancel a y, I've done it so many times before.

Thank you so much