Answer
$y=4.5e^{-0.511x}$
Work Step by Step
Use Basic Logarithmic Properties: $b^{\log_{b}x}=x$,
replacing b with e and x with $(0.6)^{x}$
$y=4.5(0.6)^{x}$ is equivalent to $y=100e^{\ln(0.6)^{x}}$\qquad
... now, by the Power Rule: $\log_{\mathrm{b}}\mathrm{M}^{\mathrm{p}}=\mathrm{p}\log_{\mathrm{b}}\mathrm{M}$
$y=4.5e^{(\ln 0.6)x}$
Calculator:
$\ln 0.6\approx$-0.510825623766 $\qquad$ ... round to 3 decimals
$\approx-0.511$,
$y=4.5e^{-0.511x}$.