Math Is Fun Forum / need explaination

pman · 2005-11-11 15:17:01

hi can someone explain in detail how to solve this kind of problem please:

Code:

 1)  7*4^x = 5*9^x

2)log3 3 + log9 1

you should use logarithms to solve it, thx!

ganesh · 2005-11-11 15:27:49

1) xlog4 + log7 = xlog9+ log5
xlog4 - xlog9 = log5 - log7
xlog9 - xlog4 = log7 - log5
x(log9 - log4) = log7 - log5
x = (log7 - log5)/(log9 - log4)

The second question isn't clear

ryos · 2005-11-11 16:32:55

I think that, on the second question, he means "log base 3 of 3 + log base 9 of 1".

If so, it's easy. 3¹ = 3, and 9^0 = 1. So, 1 + 0 = 1.

pman · 2005-11-12 05:07:14

thx alot guys

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#1 2005-11-11 15:17:01

need explaination

Code:

#2 2005-11-11 15:27:49

Re: need explaination

#3 2005-11-11 16:32:55

Re: need explaination

#4 2005-11-12 05:07:14

Re: need explaination

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#1 2005-11-11 15:17:01

need explaination

Code:

#2 2005-11-11 15:27:49

Re: need explaination

#3 2005-11-11 16:32:55

Re: need explaination

#4 2005-11-12 05:07:14

Re: need explaination

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