To find the function that represents how many more cell phones the company sells after \( x \) years than watches, we need to formulate the difference between the two functions that represent the number of cell phones and the number of watches.
-
Function for cell phones:
\( f(x) = 8x + 10 \) (in thousands) -
Function for watches:
\( g(x) = 25x + 500 \) (in thousands)
The formula that shows how many more cell phones the company sells than watches is given by:
\[
(f - g)(x) = f(x) - g(x)
\]
Substituting the functions into this equation gives:
\[
(f - g)(x) = (8x + 10) - (25x + 500)
\]
Now, we distribute the negative sign:
\[
(f - g)(x) = 8x + 10 - 25x - 500
\]
Combining like terms:
\[
(f - g)(x) = 8x - 25x + 10 - 500
\]
\[
(f - g)(x) = -17x - 490
\]
Now we have the function representing how many more cell phones are sold than watches:
\[
(f - g)(x) = -17x - 490
\]
Domain:
Since \( x \) represents the number of years, it can be any non-negative number. Therefore, the domain is:
\[
x \geq 0
\]
So, the final answer is: \[ (f - g)(x) = -17x - 490 \quad \text{and the domain is } x \geq 0. \]