If log10 5 + log10 (5x + 1) = log10 (x + 5) + 1, then x is equal to:	Choose the correct choice from the following:
A) 1 B) 5 C) 3 D) 2 E) 6

Rationale: log 10 5 + log 10 ( 5 x + 1 ) = log 10 ( x + 5 ) + 1 log 10 5 + log 10 ( 5 x + 1 ) = log 10 ( x + 5 ) + log 10 10 log 10 [ 5 ( 5 x + 1 ) ] = log 10 [ 10 ( x + 5 ) ] 5 ( 5 x + 1 ) = 10 ( x + 5 ) 5 x + 1 = 2 x + 10 3 x = 9 = > x = 3 answer c
Answer: C