SOLUTION: Suppose that log base 7 3=a, find log base 7 63. The answer is 2a+1, and I don't know why.

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: Suppose that log base 7 3=a, find log base 7 63. The answer is 2a+1, and I don't know why.      Log On


   

Question 845417: Suppose that log base 7 3=a, find log base 7 63.
The answer is 2a+1, and I don't know why.
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
log%287%2C3%29=a means 7%5E%28a%29=3
7%5E%28b%29=63
7%5E%28b%29=3%2A3%2A7
7%5E%28b%29=7%5E%28a%29%2A7%5E%28a%29%2A7
7%5E%28b%29=7%5E%282a%2B1%29
So then
log%287%2C63%29=2a%2B1