SOLUTION: Find x: log3 5 = log3 x − log3 4

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: Find x: log3 5 = log3 x − log3 4       Log On


   

Question 22298: Find x: log3 5 = log3 x − log3 4
Answer by AnlytcPhil(1806) About Me  (Show Source):
You can put this solution on YOUR website!
You need these facts:

(1)   logBA + logBC = logB(AC)

(2)   If logBA = logBC then A = C, if B > 0 and B ¹ 1

log35 = log3x − log34

Add log34 to both sides to get as many terms positive as possible

log35 + log34 = log3x

Use (1)

log3(5·4) = log3x

Rewrite 5·4 as 20

log320 = log3x  

Use (2):

20 = x

Edwin
AnlytcPhil@aol.com