A) corresponding
this is the answer hope it helps
Answer:
![f(x)=5120(1.25)^{x}](https://tex.z-dn.net/?f=f%28x%29%3D5120%281.25%29%5E%7Bx%7D)
Step-by-step explanation:
As per the given question
As we know that
f(x) and x are related by following equation
![f(x)=a( {b})^{x}](https://tex.z-dn.net/?f=f%28x%29%3Da%28%20%7Bb%7D%29%5E%7Bx%7D)
where
b is the common ratio
Now first we have to compute the value for b which are as follows
![\frac{6400}{5120}= 1.25](https://tex.z-dn.net/?f=%5Cfrac%7B6400%7D%7B5120%7D%3D%201.25)
![\frac{8000}{6400}= 1.25](https://tex.z-dn.net/?f=%5Cfrac%7B8000%7D%7B6400%7D%3D%201.25)
Like if we take the ratio by this method than it comes 1.25
Therefore the common ratio, b = 1.25
So,
a = 5,120
Hence, the equation which model the relationship between the number of weeks and the number of viewers is
![f(x)=5120(1.25)^{x}](https://tex.z-dn.net/?f=f%28x%29%3D5120%281.25%29%5E%7Bx%7D)
3x^2+12x+15=0
Then divide by 3 to get the x by itself.
x^2+4x+5=0
Factor to (x+5) (x-1) and solve for the two values of x.