1. The problem is to evaluate the expression $e^a \times 4$ where $e$ is the base of the natural logarithm and $a$ is a variable. 2. The formula used here is the exponential function $e^a$, which means $e$ raised to the power of $a$. 3. Multiplying by 4 is straightforward: $4 \times e^a$. 4. There is no further simplification unless a specific value for $a$ is given. 5. So the final expression is simply: $$4e^a$$ This means four times the exponential of $a$.