To find the function that represents how many more cell phones the company sells than watches, we will define the two functions based on the information given:
- The number of cell phones sold after \( x \) years is represented by the function \( f(x) = 8x + 10 \).
- The number of watches sold after \( x \) years is represented by the function \( g(x) = 25x + 500 \).
To find how many more cell phones the company sells than watches, we calculate \( f(x) - g(x) \):
\[ (f - g)(x) = f(x) - g(x) = (8x + 10) - (25x + 500) \]
Now, simplifying this expression:
\[ (f - g)(x) = 8x + 10 - 25x - 500 \] \[ = 8x - 25x + 10 - 500 \] \[ = -17x - 490 \]
So we have:
\[ (f - g)(x) = -17x - 490 \]
Now, regarding the domain of the function \( (f - g)(x) \), since both the functions \( f(x) \) and \( g(x) \) are linear and defined for all real numbers, the domain of \( (f - g)(x) \) is:
\[ x \geq 0 \]
Thus, the correct response is:
\[ (f - g)(x) = -17x - 490 \text{ and the domain } (f - g)(x) \text{ is } x \geq 0. \]
None of the provided responses match this conclusion. Please double-check the provided options.