Step 1: Understanding the Concept:
This is a one-step linear equation. We need to find the value of \(x\) by isolating it. Step 2: Detailed Explanation:
The given equation is:
\[ 3x = 15 \]
To solve for \(x\), divide both sides of the equation by the coefficient of \(x\), which is 3:
\[ x = \frac{15}{3} \]
\[ x = 5 \]
Step 3: Final Answer:
The value of \(x\) is 5. This corresponds to option (D).