Question

Which of the following is equivalent to 3^5 = 243?

Answer 1

log5 243 = 3

Answer 2

I don't understand the question. Is something missing?

Answer 3

no nothing is missing. its asking what log it is

Answer 4

log3243 = 5

log5243 = 3

log35 = 243

log53 = 243

Answer 5

There is a kind of rule / thing with the logarithm and exponential functions. It goes like this: log a x = y iff a^y = x. So, if you put the stuff above in, for your case ( 3^5 = 243 ) you'll see that a=3, y=5 and x = 243. Then you can use the inverse thing, which says log 3 243 = 5.

Answer 6

it is multiple choice? which one is correct?

Answer 7

i think its 5 234 = 5

Answer 8

243*

Answer 9

rewrite in equivalent exponential form and see which one is right

\[\log_b(x)=y\iff b^y=x\]

Answer 10

cus dont u put the base back where it should be..idk i remember something bout changin things around but the numbers dont change.

Answer 11

\[log_3(243) = 5\iff 3^5=243\]

Answer 12

ok so i was right

Answer 13

yes that is true!

Answer 14

log5 25 would be log 5 over log 25

Answer 15

you should be able to switch back and forth easily between
\[b^x=y\] and
\[\log_b(y)=x\] it will make your life easier (at least in math class)

Answer 16

\[\log_5(25)=y\iff 5^y=25\]

Answer 17

therefore
\[\log_5(25)=2\] because
\[5^2=25\]

Answer 18

i know but its asking what it would be for the change of base formula

Answer 19

so like fraction form

Answer 20

http://en.wikipedia.org/wiki/Logarithm#Change_of_base

Answer 21

From wikipedia:

\[ \log_b(x) = \frac{\log_k(x)}{\log_k(b)}\]

Answer 22

log b(x) is the form you currently have it in, and if you want to calculate it in some base k, then you do that by the formula given by wikipedia, on the right, up there.