Answer :
[tex]lnx=log_ex\\----------\\log_ab=c\iff a^c=b\\----------\\Domain:\\5x > 0\ \ \ |divide\ both\ sides\ by\ 5\\x > 0\\D:x\in\mathbb{R^+}\\----------------------\\2ln(5x)=8\ \ \ \ |divide\ both\ sides\ by\ 2\\\\ln(5x)=4\iff e^4=5x\\\\5x=e^4\ \ \ \ \ |divide\ both\ sides\ by\ 5\\\\\boxed{x=\frac{e^4}{5}\in D}[/tex]
