SOLUTION: If {{{5^a-5^(a-1)}}}= 2500, then a equals A) 3 B) 4 C) 5 D) 6

Algebra ->  Expressions -> SOLUTION: If {{{5^a-5^(a-1)}}}= 2500, then a equals A) 3 B) 4 C) 5 D) 6      Log On


   

Question 1042825: If 5%5Ea-5%5E%28a-1%29= 2500, then a equals
A) 3
B) 4
C) 5
D) 6
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
5%5E%28a%29+-+5%5E%28a-1%29+=+2500


5%5E%28a%29+-+5%5E%28a%29%2A5%5E%28-1%29+=+2500


5%5E%28a%29%2A%281+-+5%5E%28-1%29%29+=+2500


5%5E%28a%29%2A%281+-+1%2F5%29+=+2500


5%5E%28a%29%2A%285%2F5+-+1%2F5%29+=+2500


5%5E%28a%29%2A%28%285-1%29%2F5%29+=+2500


5%5E%28a%29%2A%284%2F5%29+=+2500


5%5E%28a%29%2A%284%2F5%29%2A%285%2F4%29+=+2500%2A%285%2F4%29


5%5E%28a%29%2A1+=+3125


5%5E%28a%29+=+3125


5%5E%28a%29+=+5%5E5


a=5


So the answer is choice C