If the domain of the function \(\displaystyle f(x) = \frac{\sqrt{x^2 - 25}}{(4 - x^2)} + \log_{10}\!\left( x^2 + 2x - 15 \right) \) is \( (-\infty, \alpha) \cup (\beta, \infty) \), then \( \alpha^2 + \beta^3 \) is equal to:
\( 150 \)
\( 175 \)
\( 125 \)
\( 140 \)