Does anyone know what is a simplified form of the expression log21(5) +log21(4) -log21(2)?

All I know is that the answer is log21 (10), but I don't know how to get that answer.

Question

Does anyone know what is a simplified form of the expression log21(5) +log21(4) -log21(2)?

All I know is that the answer is log21 (10), but I don't know how to get that answer.

ganeshie8 · Answer

use below :-
$\log a + \log b = \log (ab)$

$\log a - \log b = \log (a/b)$

anonymous · Answer

wait, is log a log 21(5) and log b log 21(4)?

ganeshie8 · Answer

$\log_{21}(5) +\log_{21}(4) -\log_{21}(2)$

ganeshie8 · Answer

$\log_{21}(5\times  4) -\log_{21}(2)$

ganeshie8 · Answer

$\log_{21}(5\times  4/2)$

ganeshie8 · Answer

$\log_{21}(20/2)$

ganeshie8 · Answer

$\log_{21}(10)$

anonymous · Answer

oh ok, thank-you

anonymous · Answer

so, do we always use that formula to solve a problem like that?

ganeshie8 · Answer

yes, u can always use that formula as long u have the same base...

ganeshie8 · Answer

base is 21 for our current problem

anonymous · Answer

oh, ok thank-you

anonymous · Answer

again

ganeshie8 · Answer

np :)