I have log4(x^2 - 9) - log4(x + 3) = 3

I get 4^3 = (x^2 - 9) / (x + 3 )

and then 64 = (x - 3)

x = 67

Correct?

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- November 20th 2008, 07:46 AMrtwiltonLog from earlier question, just need confirmation!
I have log4(x^2 - 9) - log4(x + 3) = 3

I get 4^3 = (x^2 - 9) / (x + 3 )

and then 64 = (x - 3)

x = 67

Correct? - November 20th 2008, 08:18 AMSoroban

Correct! . . . Nice work!

- November 20th 2008, 08:23 AMrtwilton
Thanks! I do have another one here I am working on and could use a jump start. Not sure how to write it. . .

Write the expression 21log3(cube root of x) + log 3(9x^2) - log 3(9) as a single logarithm.... - November 20th 2008, 10:15 AMMoo
- November 20th 2008, 10:31 AMrtwilton
I could really use the steps in between. . .I am not making the leap, sorry! I know that subtraction is division, addition is multiplication, correct??

- November 20th 2008, 11:17 AMMoo
Yep !

But don't make this mistake :

Okay, here are the steps, hope you'll know how to do further exercises later :)

~~~~~~~~~~~~~~~~~~~~~~~~~~

from the property a log(b)=log(b^a), this is :

use the rule and you'll get :

this is the main step of the leap

~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I've just seen a better way to do it :

- November 20th 2008, 11:21 AMrtwilton
Thank you so much, I can see it now. Yes, I believe I will be able to work through future problems, I hope!!