Answer:
<em>The table shows an exponential function</em>
Step-by-step explanation:
<u>Linear vs Exponential Functions</u>
A linear function is written as:
![y=mx+b](https://tex.z-dn.net/?f=y%3Dmx%2Bb)
where m and b are constants.
If a table contains a linear function, then for each pair of ordered pairs (x1,y1) and (x2,y2), the value of m must be constant.
The slope can be calculated as:
![\displaystyle m=\frac{y_2-y_1}{x_2-x_1}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20m%3D%5Cfrac%7By_2-y_1%7D%7Bx_2-x_1%7D)
An exponential function is written as:
![y=y_o.r^x](https://tex.z-dn.net/?f=y%3Dy_o.r%5Ex)
Where r is the ratio and yo is a constant.
If a table contains an exponential function, for two ordered pairs (x1,y1) and (x2,y2), the value of r must be constant.
The ratio can be calculated as:
![\displaystyle r=\sqrt[x2-x1]{\frac{y2}{y1}}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20r%3D%5Csqrt%5Bx2-x1%5D%7B%5Cfrac%7By2%7D%7By1%7D%7D)
Calculate the slope for (0,4) and (1,2):
![\displaystyle m=\frac{2-4}{1-0}=-2](https://tex.z-dn.net/?f=%5Cdisplaystyle%20m%3D%5Cfrac%7B2-4%7D%7B1-0%7D%3D-2)
Calculate the slope for (1,2) and (2,1):
![\displaystyle m=\frac{1-2}{2-1}=-1](https://tex.z-dn.net/?f=%5Cdisplaystyle%20m%3D%5Cfrac%7B1-2%7D%7B2-1%7D%3D-1)
Since the slope is not the same, the function is not linear.
Now calculate the ratio for (0,4) and (1,2)
![\displaystyle r=\sqrt[1-0]{\frac{1}{2}}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20r%3D%5Csqrt%5B1-0%5D%7B%5Cfrac%7B1%7D%7B2%7D%7D)
The radical of index 1 is simply equal to its argument:
![\displaystyle r=\frac{1}{2}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20r%3D%5Cfrac%7B1%7D%7B2%7D)
Now calculate the ratio for (0,4) and (2,1)
![\displaystyle r=\sqrt[2-0]{\frac{1}{4}}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20r%3D%5Csqrt%5B2-0%5D%7B%5Cfrac%7B1%7D%7B4%7D%7D)
![\displaystyle r=\sqrt{\frac{1}{4}}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20r%3D%5Csqrt%7B%5Cfrac%7B1%7D%7B4%7D%7D)
![\displaystyle r=\frac{1}{2}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20r%3D%5Cfrac%7B1%7D%7B2%7D)
Testing other points we'll find the same ratio, thus the table is an exponential function