Algebra
posted by Jason .
Determine if the equation y = 2^x represents exponential growth or decay
I thought at first it was growth but now I think it might be decay because there is no "b" in a parentheses so do I assume b is less than 1 so it's decay?
Please help

What happens if x > 1? What happens if x is negative or a fraction?
What does "b" have to do with this problem? 
A BALL REBOUNDS ONEHALF THE DISTANCE THAT IT FALLS. IF THE BALL IS DROOPED FROM A HEIGHT OF 512 FEET,HOW HIGH DOES IT GO ON ITS EIGHT REBOUND.