How would you change the base formula to rewrite a expression using common logarithms?

log(base7)8

Question

How would you change the base formula to rewrite a expression using common logarithms?

  log(base7)8

tkhunny · Answer

Just do it?  $\log_{7}(8) = \dfrac{\log(8)}{\log(7)}$

jdoe0001 · Answer

$\bf \textit{log change of base}\implies log_ab=\cfrac{log_{\color{red}{ c}}b}{log_{\color{red}{ c}}a}$

anonymous · Answer

So is the base always on the bottom of the fraction

jdoe0001 · Answer

yes
and "c" could be any number really, so long is the same above and below

anonymous · Answer

ahh okay, i get it. But can i ask one more question?

jdoe0001 · Answer

ok

anonymous · Answer

ok 1 second

jdoe0001 · Answer

1

jdoe0001 · Answer

hehe

anonymous · Answer

lol, how would you write this as a single logarithm.

  log$$\log_{5}4 +\log_{5}3  $$

jdoe0001 · Answer

anonymous · Answer

Oh ok so would it be $$\log_{5} (4x3) $$ ?

jdoe0001 · Answer

yeap

anonymous · Answer

:D ahh alright thank you you!

jdoe0001 · Answer

yw