121

log₁₀100=2

exp form 

10²=100

log form 

log₂8=3

exp form 

2³=8

log form 

log₅25=2

exp form 

5²=25

log form 

log₅125=3

exp form 

5³=125

log form 

log₃81=4

exp form 

3⁴=81

log form 

log₈1=0

exp form 

8⁰=1

log form 

log₄16=2

exp form 

4²=16

log form 

log₁₀1000=3

exp form 

10³=1000

log form 

log₄1/4=-1

exp form 

4^-1=1/4

log form 

log₈4=2/3

exp form 

8^2/3=4

log form 

log₅1/125=-3

exp form 

5^-3=1/125

log form 

example of undefined

(negative) 

example of undefined

(zero) 

zero

(3⁰=1)

one

(when _b=m)

log_an= logn

           loga 

y=a_*b^x

b>1 and a≥0

y=a_*b^x

0<b<1 and a≥0