Final answer:
The value of these functions is determined by the x-values to two separate function rules. Given that x = 4 which is less than 10, we will use the first part of the function to find f(4), thus f(4) equals -12.
Step-by-step explanation:
The given function is a piecewise function which is defined differently for different intervals of x. Specifically, for this question, the value of x is 4. Now we have to determine which part of the function applies for x=4. As per the given function, the first part of the function is applicable when x < 10 while the second part when x >= 10. Given that x = 4 which is less than 10, we will use the first part of the function to find f(4). So, the function is f(x) = -x - 8.
Substituting x = 4 in the function: f(4) = -(4) - 8 = -4 - 8 = -12. So, f(4) = -12 for this piecewise-defined function.
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