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## #1 2005-11-10 16:17:01

pman
Member
Registered: 2005-11-03
Posts: 10

### need explaination

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

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

2)log3 3 + log9 1``````

you should use logarithms to solve it, thx!

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## #2 2005-11-10 16:27:49

ganesh
Moderator
Registered: 2005-06-28
Posts: 21,812

### Re: need explaination

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

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #3 2005-11-10 17:32:55

ryos
Member
Registered: 2005-08-04
Posts: 394

### Re: need explaination

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.

El que pega primero pega dos veces.

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## #4 2005-11-11 06:07:14

pman
Member
Registered: 2005-11-03
Posts: 10

thx alot guys

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