SOLUTION: I have a worksheet with several problems I need help with. I have the basic rules for logarithms, but they aren't really helping. 1. 5log(base37)37^9= 2. 3log(base24)24^-2/3

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: I have a worksheet with several problems I need help with. I have the basic rules for logarithms, but they aren't really helping. 1. 5log(base37)37^9= 2. 3log(base24)24^-2/3      Log On


   



Question 71483: I have a worksheet with several problems I need help with. I have the basic rules for logarithms, but they aren't really helping.
1. 5log(base37)37^9=
2. 3log(base24)24^-2/3=
3. (Log(base7)8)/(log(base7)1/8) =
4. 10^(log(base100)9)=
Thank you in advance for your help!!!

Found 2 solutions by stanbon, josmiceli:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Remember, "log of" simply means "exponent of".

1. 5log(base37)37^9=
log(base37) 37^(9*5)
=9*5 or 45
---------------------
2. 3log(base24)24^-2/3=
log(base 24) 24^(-2/3*3)
=log(base 24) 24^(-2)
= -2
------------------
3. (Log(base7)8)/(log(base7)1/8) =
= log(base7)8 /[log(base7)1 - log(base7)8]
=log(base7)8 / -log(base7)8
= -1
-------------------------
4. 10^(log(base100)9)=
10^[(log9)/log100]
=10^[(log9)/2]
=[10^log9]^(1/2)
=9^(1/2)
=3
---------------
Cheers,
Stan H.





Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The best way to deal with logs is to think up a very simple
example that will show you how to do a problem, for instance,
What's log%282%2C16%29? Note that 16+=+2%2A2%2A2%2A2+=+2%5E4.
Say to yourself, What's the log to the base 2 that gives me
2%5E4? You see that it's 4.
------------------
5log%2837%2C37%5E9%29
5%2A9 (exactly like my example above)
45 answer
------------------
3log%2824%2C24%5E%28-2%2F3%29%29
3%2A%28-2%2F3%29
-2 answer
--------------------
Log%287%2C8%29%2Flog%287%2C1%2F8%29
Note the general rule that log(a/b) = log(a) - log(b) (with any base)
and also log(1) = 0 (with any base)
log%287%2C8%29+%2F+%28log%287%2C1%29+-+log%287%2C8%29%29
log%287%2C8%29+%2F+%280+-+log%287%2C8%29%29
-%28log%287%2C8%29%29+%2F+log%287%2C8%29+=+-1
--------------------
10%5E%28log%28100%2C9%29%29
x+=+log%28100%2C9%29
100%5Ex+=+9
10%5E%282x%29+=+9
10%5E2%2A10%5Ex+=+9
10%5Ex+=+9%2F100
10%5E%28log%28100%2C9%29%29+=+9%2F100