If log ⁑ 10 5 + log ⁑ 10 ( 5 π‘₯ + 1 ) = log ⁑ 10 ( π‘₯ + 5 ) + 1 log 10 ​ 5+log 10 ​ (5x+1)=log 10 ​ (x+5)+1, find π‘₯ x.

Difficulty: Medium

Correct Answer: 3

Explanation:

Given data & domain

  • 5x+1 > 0, x+5 > 0 (log arguments must be positive).

Concept / Approach

  • Use log properties: log ⁑ π‘Ž + log ⁑ 𝑏 = log ⁑ ( π‘Ž 𝑏 ) loga+logb=log(ab) and 1 = log ⁑ 10 10 1=log 10 ​ 10.

Step-by-step calculation
log ⁑ 10 [ 5 ( 5 π‘₯ + 1 ) ] = log ⁑ 10 [ 10 ( π‘₯ + 5 ) ] log 10 ​ [5(5x+1)]=log 10 ​ [10(x+5)] β‡’ 25 π‘₯ + 5 = 10 π‘₯ + 50 β‡’25x+5=10x+50 15 π‘₯ = 45 β‡’ π‘₯ = < π‘š π‘Ž π‘Ÿ π‘˜ > 3 < / π‘š π‘Ž π‘Ÿ π‘˜ > 15x=45β‡’x=3

Verification
5x+1 = 16 > 0, x+5 = 8 > 0 valid. Substitute to check equality.

Final Answer
3

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