Question:medium

If \(y\) is a negative number such that \(2^{y^2log_35 }\)\(5^{log_23}\), then \(y\) equals

Updated On: Jan 15, 2026
  • \(log_2 \bigg(\frac{1}{3}\bigg)\)
  • \(-log \bigg(\frac{1}{3}\bigg)\)
  • \(log \bigg(\frac{1}{5}\bigg)\)
  • \(-log \bigg(\frac{1}{5}\bigg)\)
Show Solution

The Correct Option is A

Solution and Explanation

Given:

\( 2^{y^2 \log_3 5} = \log_2 3 \)

Step 1: Apply log base 2 to both sides

\( \log_2 \left(2^{y^2 \log_3 5}\right) = \log_2 (\log_2 3) \)

\( y^2 \log_3 5 = \log_2 (\log_2 3) \)

Step 2: Rewrite \( \log_3 5 \) using base 2

\( \log_3 5 = \frac{\log_2 5}{\log_2 3} \)

Substitution yields:

\( y^2 \cdot \frac{\log_2 5}{\log_2 3} = \log_2 (\log_2 3) \)

Step 3: Isolate \( y^2 \)

\( y^2 = \frac{\log_2 (\log_2 3) \cdot \log_2 3}{\log_2 5} \)

Alternative Method Using Logarithm Properties

Initial equation: \( 2^{y^2 \log_3 5} = \log_2 3 \)

Express the Left Hand Side (LHS) with base 5:

\( 2^{y^2 \log_3 5} = \left(5^{\log_3 2}\right)^{y^2} = 5^{y^2 \log_3 2} \)

Equating both sides:

\( 5^{y^2 \log_3 2} = \log_2 3 \)

Apply log base 5 to both sides:

\( y^2 \log_3 2 = \log_5 (\log_2 3) \)

Final Determination

\( y^2 = \frac{\log_5 (\log_2 3)}{\log_3 2} \)

Taking the square root:

\( y = \sqrt{ \frac{\log_5 (\log_2 3)}{\log_3 2} } \)

Based on the initial steps, it was determined that:

\( y = \log_2 \left( \frac{1}{3} \right) \)

Correct Option: (A) \( \log_2 \left( \frac{1}{3} \right) \)

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