Exponential funcitons whose graph pass through (3,7) (8,15)

[tklopfstein]

Help! I am a high school student and I have a final exam tomorrow. I am struggling with exponential functions. Can you please tell me how to write an exponential function for the graph that would pass through these points?

(3,7) (8,15)


Thanks so much,

Johnny

 

[Gene]

There are MANY types of exponential equations. y=ae^(0)x+b might be considered one but that would just be a linear.
y=ae^(bx) is quite popular. Just in case:
7=ae^(2b)
15=ae^(8b)
Dividing
15/7=e^(6b)
6b=ln(15/7)
b=ln(15/7)/6 = .127
a=7/e^(2*.127) = 5.43 gives
y=5.43e^(.127x)

If you have something else in mind, you'll have to supply a model.

PS Whoops, I did (2,7) and (8,15) but the model is good.