To determine when Salim's motorcycle will be worth $7000, we want to solve the following equation based on the depreciation function:
\[ f(x) = 14000(1 - 0.09)^x \]
Setting \( f(x) \) equal to $7000:
\[ 7000 = 14000(1 - 0.09)^x \]
First, simplify the equation:
\[ \frac{7000}{14000} = (1 - 0.09)^x \]
This simplifies to:
\[ 0.5 = (0.91)^x \]
Now, we will take the logarithm of both sides to solve for \( x \):
\[ \log(0.5) = x \cdot \log(0.91) \]
Now, we can isolate \( x \):
\[ x = \frac{\log(0.5)}{\log(0.91)} \]
Now, using a calculator:
\[ \log(0.5) \approx -0.3010 \] \[ \log(0.91) \approx -0.0434 \]
Now, calculate \( x \):
\[ x \approx \frac{-0.3010}{-0.0434} \approx 6.93 \]
Thus, the motorcycle will be worth $7000 in approximately 7 years.
So the correct response from the given options would be:
7 years.