How do you condense #log 40 - log 4 #? Precalculus Properties of Logarithmic Functions Common Logs 1 Answer Bhavin B. May 11, 2018 #log40-log4# = #log(40/4)# = #log10 = 1# Explanation: Use the quotient property of logarithms, #log_b(x)-log_b(y)# = #log_b(x/y)# #log40-log4# = #log(40/4)# = #log10 = 1# Note: #log_b(b)=1# ---> hence #log_10(10) = 1# 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 3350 views around the world You can reuse this answer Creative Commons License