Step 1: Apply the product rule.
We are given that \( f(x) = e^x g(x) \). To find \( f'(x) \), we use the product rule:
\[
f'(x) = \frac{d}{dx} \left( e^x \right) g(x) + e^x \frac{d}{dx} \left( g(x) \right)
\]
This simplifies to:
\[
f'(x) = e^x g(x) + e^x g'(x)
\]
Step 2: Evaluate at \( x = 0 \).
Now, substituting the known values at \( x = 0 \):
\[
f'(0) = e^0 \cdot g(0) + e^0 \cdot g'(0) = 1 \cdot 4 + 1 \cdot 2 = 6
\]
Step 3: Conclusion.
Thus, the value of \( f'(0) \) is \( \boxed{6} \).