1. The problem is to simplify the expression $(3)5$. 2. This expression means multiplying 3 by 5. 3. The formula for multiplication is $a \times b = c$ where $a$ and $b$ are numbers and $c$ is their product. 4. Applying the formula: $3 \times 5 = 15$. 5. Therefore, the simplified result of $(3)5$ is $15$.