Aptitude - Logarithm - Discussion

Discussion Forum : Logarithm - General Questions (Q.No. 9)
9.
If log10 5 + log10 (5x + 1) = log10 (x + 5) + 1, then x is equal to:
1
3
5
10
Answer: Option
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.

Discussion:
14 comments Page 2 of 2.

Abdur Rafay said:   8 years ago
How the 1 turned into log10 10? Please explain.

Bhavya said:   8 years ago
Log10 10=1 so place of1 they take log10 10.
(1)

Vijju said:   5 years ago
@Chi.

How log 10 10 = 1?

Ashmi said:   8 years ago
How logx x=1?


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