1. The problem is to simplify the expression $-25ct + 5$. 2. This expression consists of two terms: $-25ct$ and $5$. 3. Since these terms are not like terms (one contains variables $c$ and $t$, the other is a constant), they cannot be combined further. 4. Therefore, the simplified form of the expression is simply $-25ct + 5$. This expression is already in its simplest form because it contains unlike terms. Final answer: $-25ct + 5$