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# Logarithms question watch

1. Log base 3 (4x + 7)/x = 2

I used the log law ...Log base a X = y , a^y = X

and got 3^2 = (4x + 7)/2

However in the mark scheme there is a mark for stating or implying 2 = log base 3 9... I did not state this but still got the correct answer using my above method would I still get full marks?
2. it seems unfair for penalising you. Your method works fine. It is true that 2 can be written as log39 but that should be asked as a separate question really.
3. (Original post by the bear)
it seems unfair for penalising you. Your method works fine. It is true that 2 can be written as log39 but that should be asked as a separate question really.

Ok thank you... I guess it would depend on the mood of the examiner.
4. (Original post by IShouldBeRevising_)
Log base 3 (4x + 7)/x = 2

I used the log law ...Log base a X = y , a^y = X

and got 3^2 = (4x + 7)/2

However in the mark scheme there is a mark for stating or implying 2 = log base 3 9... I did not state this but still got the correct answer using my above method would I still get full marks?
surely at some point you changed that 3^2 into 9 (or 18)

thus, implied
5. Sorry for this stupid question but why did x become 2?
6. (Original post by JerzyDudek)
Sorry for this stupid question but why did x become 2?
There's a 2 on the RHS of the equation and you can think of this as the log to base 3 of 9.
7. (Original post by davros)
There's a 2 on the RHS of the equation and you can think of this as the log to base 3 of 9.
But , isn't it?

Edit: there is no 3 outside the brackets, sorry.
8. (Original post by JerzyDudek)
But , isn't it?
You're correct.

Either there's a typo in the OP's question or there's a typo/mistake in his working.
9. (Original post by JerzyDudek)
But , isn't it?
You're quite right...I hadn't spotted the OP's subtle replacement of x with 2 on the LHS!

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Updated: March 10, 2013
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