We are given with the table of x and y values
We use the given y values to find the required equation
When the first difference between the y values are same then it is linear.
When the common ratio between y values are same then it is exponential.
When the second difference of y values are same then it is quadratic.
Lets find the difference between y values
![\frac{1}{4} - \frac{1}{8} = \frac{1}{8}](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B4%7D%20-%20%5Cfrac%7B1%7D%7B8%7D%20%3D%20%5Cfrac%7B1%7D%7B8%7D)
![\frac{1}{2} - \frac{1}{4} = \frac{1}{4}](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B2%7D%20-%20%5Cfrac%7B1%7D%7B4%7D%20%3D%20%5Cfrac%7B1%7D%7B4%7D)
![1 - \frac{1}{2} = \frac{1}{2}](https://tex.z-dn.net/?f=%201%20-%20%5Cfrac%7B1%7D%7B2%7D%20%3D%20%5Cfrac%7B1%7D%7B2%7D)
The difference is not same . so we cannot choose y= mx+b
Now we find the common difference between y values
![\frac{\frac{1}{4}}{\frac{1}{8}} = 2](https://tex.z-dn.net/?f=%5Cfrac%7B%5Cfrac%7B1%7D%7B4%7D%7D%7B%5Cfrac%7B1%7D%7B8%7D%7D%20%3D%202)
![\frac{\frac{1}{2}}{\frac{1}{4}} = 2](https://tex.z-dn.net/?f=%5Cfrac%7B%5Cfrac%7B1%7D%7B2%7D%7D%7B%5Cfrac%7B1%7D%7B4%7D%7D%20%3D%202)
![\frac{1}{\frac{1}{2}} = 2](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B%5Cfrac%7B1%7D%7B2%7D%7D%20%3D%202)
The common ratio is 2. So its exponential.
The required equation ![y=ab^x](https://tex.z-dn.net/?f=y%3Dab%5Ex)