1. The problem is to understand the function notation $d(t)$, which typically represents a function named $d$ with the variable $t$. 2. In mathematics, $d(t)$ means the value of the function $d$ at the input $t$. 3. For example, if $d(t) = 2t + 3$, then to find $d(4)$, substitute $t=4$: $$d(4) = 2(4) + 3 = 8 + 3 = 11$$ 4. Function notation helps us express relationships where one quantity depends on another. 5. Without a specific formula or context, $d(t)$ just denotes a function dependent on $t$. This explanation covers the meaning and use of $d(t)$ in algebra and functions.