SOLUTION: Hi I dont understand how to do this problem. The chapter is on exponential and logarithmic functions. the problem on writing an exponential function from two points on the functi

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: Hi I dont understand how to do this problem. The chapter is on exponential and logarithmic functions. the problem on writing an exponential function from two points on the functi      Log On


   

Question 131694: Hi I dont understand how to do this problem. The chapter is on exponential and logarithmic functions. the problem on writing an exponential function from two points on the functions graph.
Heres the question
Write an exponential function of the form y=ab^x that includes the given points. (1,2) (2,8)
Thanks alot
Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
You are given y=ab%5Ex.

(1,2)
2=ab^1
ab=2


(2,8)
8=ab^3
ab*b^2=8 Substitute ab=2

2b^2=8
b^2=4
b=2 (assume base number to be a positive number!)

ab=2, where b=2
a=1

y=ab%5Ex
y=2%5Ex

For additional explanation, please see my own website by clicking on my tutor name anywhere in algebra.com. Look for MATH IN LIVING COLOR, and go to College Algebra, Chapter 4. I'm thinking about posting my entire explanation of Logarithms in the near future, when I get time to do so.

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