Question and Answers Forum

All Questions      Topic List

Logarithms Questions

Previous in All Question      Next in All Question      

Previous in Logarithms      Next in Logarithms      

Question Number 86339 by frempongfaustina24@gmail.com last updated on 28/Mar/20

4^x +6^x =9^x

$$\mathrm{4}^{{x}} +\mathrm{6}^{{x}} =\mathrm{9}^{{x}} \\ $$$$ \\ $$$$ \\ $$

Answered by jagoll last updated on 28/Mar/20

((2/3))^(2x) +((2/3))^x =1  let ((2/3))^x  = t  t^2 + t = 1 ⇒ t^2 +t−1=0  now it easy to solve

$$\left(\frac{\mathrm{2}}{\mathrm{3}}\right)^{\mathrm{2x}} +\left(\frac{\mathrm{2}}{\mathrm{3}}\right)^{\mathrm{x}} =\mathrm{1} \\ $$$$\mathrm{let}\:\left(\frac{\mathrm{2}}{\mathrm{3}}\right)^{\mathrm{x}} \:=\:\mathrm{t} \\ $$$$\mathrm{t}^{\mathrm{2}} +\:\mathrm{t}\:=\:\mathrm{1}\:\Rightarrow\:\mathrm{t}^{\mathrm{2}} +\mathrm{t}−\mathrm{1}=\mathrm{0} \\ $$$$\mathrm{now}\:\mathrm{it}\:\mathrm{easy}\:\mathrm{to}\:\mathrm{solve} \\ $$

Terms of Service

Privacy Policy

Contact: info@tinkutara.com