Answer:
The rate of change is -5
The initial value is 25
Step-by-step explanation:
Since, this is a linear relation
so, we can select any two points and find equation of line
points are (1,20) and (3,10)
so,
![x_1=1,y_1=20](https://tex.z-dn.net/?f=x_1%3D1%2Cy_1%3D20)
![x_2=3,y_2=10](https://tex.z-dn.net/?f=x_2%3D3%2Cy_2%3D10)
now, we can find slope
![m=\frac{y_2-y_1}{x_2-x_1}](https://tex.z-dn.net/?f=m%3D%5Cfrac%7By_2-y_1%7D%7Bx_2-x_1%7D)
now, we can plug values
![m=\frac{10-20}{3-1}](https://tex.z-dn.net/?f=m%3D%5Cfrac%7B10-20%7D%7B3-1%7D)
![m=-5](https://tex.z-dn.net/?f=m%3D-5)
now, we can use point slope form of line
![y-y_1=m(x-x_1)](https://tex.z-dn.net/?f=y-y_1%3Dm%28x-x_1%29)
now, we can plug values
![y-20=-5(x-1)](https://tex.z-dn.net/?f=y-20%3D-5%28x-1%29)
now, we can solve for y
![y=-5x+25](https://tex.z-dn.net/?f=y%3D-5x%2B25)
we know that
slope is the rate of change
So, the rate of change is -5
For finding initial value , we can plug x=0 and find y
![y=-5\times 0+25](https://tex.z-dn.net/?f=y%3D-5%5Ctimes%200%2B25)
![y=25](https://tex.z-dn.net/?f=y%3D25)
So, initial value is 25