Answer :
[tex]\ln 4^{x+3}=\ln 3^{-x}[/tex]
Using the properties of logarithms we have that:
[tex]\begin{gathered} 4^{x+3}=3^{-x} \\ \log _2(4^{x+3})=\log _2(3^{-x}) \\ 2(x+3)=-x\log _2(3) \\ 2x+6=-x\log _2(3) \\ 2x+x\log _2(3)=-6 \\ x(2+\log _2(3))=-6 \\ x=-\frac{6}{2+\log _2(3)} \end{gathered}[/tex]x has a value of -6/(2+log₂(3))