Answer:
B. 7.3 years
Explanation:
The question is wrong. The correct function is :

We have the function
that represents the value of a piece of farm equipment after
years.
This means that when
its original value is :

Now we want to calculate approximately when will its value be half its original value. Then, we write :

is half of its original value. We need to find
that satisfies the following equation :

Solving for
:
⇒

Now we apply natural logarithm to each side of the equation :
![ln(0.5)=ln[(0.91)^(x)]](https://img.qammunity.org/2021/formulas/mathematics/college/37qy7e4ekw362i5drmr4psw9vbcauv27z8.png)
Using logarithm properties :
⇒
![ln(0.5)=x[ln(0.91)]](https://img.qammunity.org/2021/formulas/mathematics/college/ddxqway906l5mf4twhsr0h55o30qwzoumr.png)
⇒
≅

The correct option is B. 7.3 years