1. The problem states that the function domain is $0 \leq x \leq 4$, meaning $x$ can take any value from 0 to 4 inclusive. 2. This defines a horizontal line segment on the number line starting at $x=0$ and ending at $x=4$. 3. The domain restriction means any function or expression involving $x$ is only valid within this interval. 4. For example, if you have a function $C(x)$ defined on this domain, you only consider values of $x$ between 0 and 4. 5. This is important for evaluating, graphing, or solving equations involving $C(x)$ because outside this domain, the function is not defined or not considered. Final answer: The domain of $x$ is the closed interval $$[0,4]$$ meaning $x$ can be any value such that $0 \leq x \leq 4$.