# Thread: Need quick help with logarithms

1. ## Need quick help with logarithms

I am currently helping someone with their online school work. If they do not get it done within the next couple of hours, they will be denied their high school diploma. They were failed due to absences, and the online class covers much more than they were required to go over in public school.

1. if logb3=0.23 and logb8 = 0.71, find logb24

2. ## Re: Need quick help with logarithms

Hint: use the property of logs:

$\log_b(x)+\log_b(y)=\log_b(xy)$

3. ## Re: Need quick help with logarithms

So I would just do (.23)x(.71) and get .1633?

4. ## Re: Need quick help with logarithms

No, you want to add:

$\log_b(3)+\log_b(8)=\log_b(24)$

Now, substitute the given values for the log functions on the left.

5. ## Re: Need quick help with logarithms

Oh! Wow, that was pretty silly of me. Thanks!

Would you mind helping explain how to expand and condense logarithmic equations?

For instance: log2((7(p-3))6/q2r)

6. ## Re: Need quick help with logarithms

Could some of you please go over to my question and help me out? I need to turn these 3 questions in very soon. PLEASE HELP!

7. ## Re: Need quick help with logarithms

Originally Posted by Chace
Oh! Wow, that was pretty silly of me. Thanks!

Would you mind helping explain how to expand and condense logarithmic equations?

For instance: log2((7(p-3))6/q2r)
There are some properties you may use:

$\log_a\left(b^c\right)=c\cdot\log_a(b)$

$\log_a(bc)=\log_a(b)+\log_a(c)$

$\log_a\left(\frac{b}{c}\right)=\log_a(b)-\log_a(c)$

Do you see how to apply these to expand the expression you posted?

8. ## Re: Need quick help with logarithms

Here is a better image of the problem I was referring to.

Would it be:

6log27+6log2(p-3)-2log2q+log2r?

9. ## Re: Need quick help with logarithms

Very close, but the last term needs a minus sign in front as r was in the denominator.

10. ## Re: Need quick help with logarithms

Here's another problem!

I am inclined to go with A. Thoughts?

11. ## Re: Need quick help with logarithms

It's not A since the exponent 3 was not on the 18...

12. ## Re: Need quick help with logarithms

Ah, too true. I feel as if B is the correct answer.

The reason I say this is because in C, the coefficient "2" should also apply to the log9, correct?

Also: in D, I don't believe the 4 corresponds to everything that it should.

13. ## Re: Need quick help with logarithms

Yes, your reasoning is correct.