If log10 5 + log10 (5x + 1) = log10 (x + 5) + 1, then x is equal to:
Choose the correct option: A) 15 B) 8 C) 9 D) 3 E) 10
Explanation:   log10 5 + log10 (5x + 1) = log10 (x + 5) + 1   log10 5 + log10 (5x + 1) = log10 (x + 5) + log10 10   log10 [5 (5x + 1)] = log10 [10(x + 5)]   5(5x + 1) = 10(x + 5)   5x + 1 = 2x + 10   3x = 9   x = 3.   answer 3
<result>D</result>
If log10 5 + log10 (5x + 1) = log10 (x + 5) + 1, then x is equal to: