Identify Exponential Function from Ordered Pairs

Published on March 3, 2026

Functions

Determine which set of ordered pairs conforms to the general form of an exponential function y = a*b^x by testing points, especially the y-intercept (0, a).

Question

Answer

An exponential function has the general form , where is the initial value (the -intercept when ) and is the base (the common ratio).
We will test each set of ordered pairs to see if they can fit this form for some constants and .
A crucial feature of most standard exponential functions is that if is a point, then . The -intercept is . If is a point, then , which implies . If , the function is , which is the constant function . If the set contains points other than , it cannot be the function .
Let’s examine the options:
Option 1:
This set contains , which implies . If , then for all . However, the set also contains , where . Therefore, this set cannot be generated by an exponential function.
Option 2:
This set also contains , implying and thus for all . Since and have , this set cannot be generated by an exponential function.
Option 3:
This set contains .
Using :
For :
So, the function must be .
Now we use the other points to find :
For :
The potential function is . Let’s check the remaining points with :
For :
This matches the point .
For :
This matches the point .
Since all points fit the form , this set could be generated by an exponential function.
Option 4:
This set contains , implying and thus for all . Since and have , this set cannot be generated by an exponential function.
The only set that fits the form is Option 3.
The correct set of ordered pairs is .
The final answer is the third option.