3.87: Exponential model from a straight-line log graph

Variables $x$ and $y$ are such that when $\ln y$ is plotted against $x$ a straight-line graph is obtained. The line passes through $(1,\ \ln 15)$ and $(2,\ \ln 75)$. Show that $y = Ab^{x}$ where $A$ and $b$ are integers to be found.