For this problem, we are told to use the natural logarithm when solving. So, to do that, we take the natural logarithm of both sides. Recall the following properties of logarithms: $$log_a(x\cdot y)=\log_a(x)+\log_a(y)$$ $$\log_a(x/ y)=\log_a(x)-\log_a(y)$$ $$\log_a(x^y)=y\log_a(x)$$ $$\log_a(a^x)=x$$ $$a^{\log_a(x)}=x.$$