How do you solve #400/(1+e^-x)=350#? Precalculus Solving Exponential and Logarithmic Equations Logarithmic Models 1 Answer A. S. Adikesavan Jan 4, 2017 ln 7 Explanation: Cross multiplying and rearranging, #r^(-x)=1/7#. The reciprocal #e^x=7#. Inversely, #x = ln 7#. Answer link Related questions What is a logarithmic model? How do I use a logarithmic model to solve applications? What is the advantage of a logarithmic model? How does the Richter scale measure magnitude? What is the range of the Richter scale? How do you solve #9^(x-4)=81#? How do you solve #logx+log(x+15)=2#? How do you solve the equation #2 log4(x + 7)-log4(16) = 2#? How do you solve #2 log x^4 = 16#? How do you solve #2+log_3(2x+5)-log_3x=4#? See all questions in Logarithmic Models Impact of this question 2289 views around the world You can reuse this answer Creative Commons License