# Without graphing, how do you determine whether each equation Y=72(1.6)^x represents exponential growth of exponential decay?

$1.6 > 1$ so every time you raise it to the power $x$ (increasing) it gets bigger:
if $x = 0 \to {1.6}^{0} = 1$
and if $x = 1 \to {1.6}^{1} = 1.6 > 1$
Already increasing $x$ from zero to 1 made your value increase!