## Functions Modeling Change: A Preparation for Calculus, 5th Edition

$x\approx8.663$
Take the log of both sides to get $$\log {1.45^x}=\log 25$$ Since $\log a^b=b \log a$, the expression becomes $$x \log 1.45 = \log 25$$ Therefore, dividing each side by $\log 1.45$ gives $$x=\frac{\log25}{\log 1.45}\approx8.663$$