A relationship refers to how your independant variable relates to your dependant variable. Exponential relationships means that your y value increases exponentially to the x variable. This is written as y=a^x

If y=3^x, and your x started at 0 and increased by 1's, you would have

y=3^0 = 1

y=3^1 = 3

y=3^2 = 9

y=3^3 = 27

y=3^4 = 81

y=3^5 = 243

and etc.

Hope this helps you but if it doesn't, then tell me specifically what it is you don't understand.

- Jordan