To find the function that represents how many more cell phones the company sells after \(x\) years than watches, we need to compute the difference between the two functions for cell phones \( f(x) = 8x + 10 \) and watches \( g(x) = 25x + 500 \).
The difference \( (f - g)(x) \) is calculated as follows:
\[ (f - g)(x) = f(x) - g(x) \]
Substituting the functions:
\[ (f - g)(x) = (8x + 10) - (25x + 500) \]
Now, simplifying:
\[ (f - g)(x) = 8x + 10 - 25x - 500 \] \[ (f - g)(x) = 8x - 25x + 10 - 500 \] \[ (f - g)(x) = -17x - 490 \]
So the function representing how many more cell phones the company sells after \(x\) years than watches is:
\[ (f - g)(x) = -17x - 490 \]
Next, regarding the domain: since \(x\) represents the number of years and it cannot be negative, the domain is \( x \geq 0 \).
Thus, the final result is: \[ (f - g)(x) = -17x - 490 \quad \text{and the domain is} \quad x \geq 0. \]
Therefore, the correct response is: \((f-g)(x)=-17x-490\) and the domain \((f-g)(x)\) is \(x \geq 0\).