Final answer:
The input value -4 is undefined in the given function because it falls outside the defined range of inputs.
Step-by-step explanation:
In the given function, f(x) = 2; -2-3; 2, the input value -4 is undefined. This is because the function does not have a defined output for x = -4. The function only provides outputs for x values between 0 and 20, inclusive.