Step 1: Solve for \( \alpha \) and \( \beta \)
Using Cramer’s rule:
\[
\alpha = \frac{\Delta_1}{\Delta}, \quad \beta = \frac{\Delta_2}{\Delta}
\]
Computing determinants, we find:
\[
\alpha = 2, \quad \beta = 1
\]
Step 2: Compute \( \alpha^2 + \beta^2 \)
\[
\alpha^2 + \beta^2 = 2^2 + 1^2 = 4 + 1 = 5
\]
Thus, the correct answer is 5.