We are given with a equation i.e ;
[tex]{:\implies \quad \sf e^{3x}-4=3}[/tex]
Transpose 4 to Right-Hand-Side ;
[tex]{:\implies \quad \sf e^{3x}=7}[/tex]
Now , Taking Natural logarithm to both sides ;
[tex]{:\implies \quad \sf ln(e^{3x})=ln(7)}[/tex]
[tex]{:\implies \quad \sf 3x \: ln(e)=ln(7) \quad \qquad \{\because ln(a^{b})=b\: ln(a)\}}[/tex]
[tex]{:\implies \quad \sf 3x=ln(7) \quad \qquad \{\because ln(e)=1\}}[/tex]
[tex]{:\implies \quad \bf \therefore \quad \underline{\underline{x=\dfrac{ln(7)}{3}}}}[/tex]