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The equation is

$64(12)^{8x} = 195$

the steps I have done so far.

  • $12^{8x} = 195/64$
  • $8x \cdot \ln(12) = \ln(195/64)$
  • $8x = (\ln(195/64))/(\ln(12))$

not sure how to divide $8x$ to get $x$ by itself for the final answer with the ln's

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6  
Wait a minute --- you've done all the log stuff, now you're down to $8x=A$, and you can't solve that for $x$? –  Gerry Myerson Dec 4 '12 at 23:36
    
@GerryMyerson that is correct. I took a break from math for about 8 months and I know you divide 8 on both sides, but the ln's are confusing me. –  Tyler Zika Dec 4 '12 at 23:37
    
Don't let them confuse you! Dividing by $8$ is dividing by $8$, no matter what the other side of the equation looks like. What would you do if it were $8x=93/42$? –  Gerry Myerson Dec 4 '12 at 23:38
    
@GerryMyerson x = 8(93/42)? –  Tyler Zika Dec 4 '12 at 23:40
    
@GerryMyerson oh its x = 93/336 –  Tyler Zika Dec 4 '12 at 23:43

1 Answer 1

up vote 3 down vote accepted

when you divide $8x = (\ln(195/64))/\ln(12)$ you get $x = (\ln(195/64))/(\ln(12)(8))$. The 8 only affects the bottom denominator of equation when you divide a fraction. thank you @GerryMyerson

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It's better to write $x=\frac{\ln(195/64)}{8\ln(12)}$ using the code $x=\frac{\ln(195/64)}{8\ln(12)}$. See MathJax basic tutorial and quick reference. –  Américo Tavares Dec 5 '12 at 0:15
    
@AméricoTavares thanks, I don't understand how that code works yet. Do you know of any great tutorials? –  Tyler Zika Dec 5 '12 at 0:18
    
For some basic information about writing math at this site see e.g. here, here, here and here. –  Américo Tavares Dec 5 '12 at 0:19

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