Step 1: Condition for Eliminating \( x^3 \) Term
Using the transformation \( x \to x + h \), the coefficient of \( x^3 \) must vanish.
Step 2: Solve for \( h \)
\[
\text{Coefficient of } x^3 \text{ in transformed equation} = 0
\]
Solving, we obtain:
\[
h = -\frac{1}{2}
\]
Thus, the correct answer is \( -\frac{1}{2} \).