I want to know how to enter basic logs into the calculator: Example. Log3^9=2 How can you enter this into the calculator?

Syntax errors. Check you are inputting your data in the correct order.

Enter the base as the second argument, following a comma. For your example, enter it as logBASE(X,2) .

Is the original problem (log 10,000 - log 1,000) / (4 log 1.0125) ? If so, press
( 1 0 0 0 0 LOG - 1 0 0 0 LOG ) / ( 4 * 1 . 0 1 2 5 LOG =
and you should see the expected result.

For the inverse natural log, press 2nd LN. For the inverse common log, press 2nd LOG.

For example, to calculate the inverse natural log of 2, press 2nd LN 2 ENTER and you'll get about 7.389 .

1 0 * 4 LOG =

For common logarithm use the LOG key just below the blue 2nd key. For natural logarithm use the LN key just below the LOG key.

In either case, press the appropriate key, then type in the expression whose log you want, then the ) key. Type in whatever else there might be in the total expression, then the ENTER key.

For example, to calculate the natural log of 2:
LN 2 ) ENTER

Use the log function (common logarithm). See screen capture for markings on key.

To evaluate the negative of a logarithm
Enter the number (argument) of the logarithm
Press the = key to have it calculated.
While result is still displayed, press the sign change key or (+/-).

Beware that -log(number) is not necessarily a negative value.

Another way to calculate -log is to use the relation
log(1/a)=-log(a) .

Your example

3 [EXP] [(] [+/-] 2 [) ] [LOG][=] [+/-]

[EXP] is the key to enter exponent of a power of 10 :It is a shortcut, so no 10 is entered. Respect the key sequence above.
[ (] left parenthesis to prevent ambiguity due to the negaticve exponent. Just a security.
[)] is the enclosing right parenthesis
[+/-] is the Sign Change key

Hi ;

for log base 10 use the the "log" key

example :

log(2) + log(3) = log(6)

enter 2 press the log key you will get 0.30102999 press the '+" key than 3 log you should get 0.47712125 for it Press the "=" or enter and you should get 0.778151250 for a answer than press inv or 2nd log and you should get 6 for a answer

and that all there is to it

The antilog is the inverse of the logarithm. Not too surprisingly, it's invoked as the 2ND shift of the appropriate log key.

For the common antilog, use the 10^x key (2ND LOG). For example, 2ND LOG 3 ENTER gives 1000 as the common antilog of 3.

For the natural antilog, use the e^x key (2ND LN). For example, 2ND LN 3 ENTER gives 20.08553692 as the natural antilog of 3.

In any scientific calculator log2(n) can be  calculated with either ln or log function as follows
 
Log2(n)= ln(n) / ln(2)
 
Or
Log2(n)=log(n) / log(2)

both will give nearly the same answers