How do you find the value of #log_(1/2) 15# using the change of base formula? Precalculus Properties of Logarithmic Functions Common Logs 1 Answer Shwetank Mauria Feb 3, 2017 #log_(1/2)15=-3.9073# Explanation: #log_ab=logb/loga# Hence, #log_(1/2)15# = #log15/log(1/2)# = #log15/(log1-log2)# = #log15/(0-log2)# = #1.1761/(-0.3010)=-3.9073# Answer link Related questions What is the common logarithm of 10? How do I find the common logarithm of a number? What is a common logarithm or common log? What are common mistakes students make with common log? How do I find the common logarithm of 589,000? How do I find the number whose common logarithm is 2.6025? What is the common logarithm of 54.29? What is the value of the common logarithm log 10,000? What is #log_10 10#? How do I work in #log_10# in Excel? See all questions in Common Logs Impact of this question 2337 views around the world You can reuse this answer Creative Commons License