How do you solve #4^(x +4) = 5^((2x)/ 5)#? Precalculus Solving Exponential and Logarithmic Equations Logarithmic Models 1 Answer Bdub Apr 21, 2016 #x=(4ln4)/(ln4-2/5 ln5)~~7.47# Explanation: #ln 4^(x+4)=ln 5^(2/5 x)# #(x+4)ln4=2/5 xln5# #xln4+4ln4-2/5 x ln5=0# #xln4-2/5 x ln5=4ln 4# #x(ln4-2/5 ln5)=4ln4# #x=(4ln4)/(ln4-2/5 ln5)~~7.47# 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 3424 views around the world You can reuse this answer Creative Commons License