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If the domain of the function $$f(x) = \frac{\sqrt{x^2 - 25}}{4 - x^2} + \log_{10}(x^2 + 2x - 15)$$ is $$(-\infty, \alpha) \cup [\beta, \infty)$$, then $$\alpha^2 + \beta^3$$ is equal to:
Find $$\alpha^2 + \beta^3$$ for the domain $$(-\infty, \alpha) \cup [\beta, \infty)$$ of $$f(x) = \frac{\sqrt{x^2-25}}{4-x^2} + \log_{10}(x^2+2x-15)$$.
Requires $$x^2 - 25 \geq 0$$, i.e., $$x^2 \geq 25$$.
$$x \leq -5$$ or $$x \geq 5$$.
$$x^2 \neq 4$$, so $$x \neq \pm 2$$.
Combined with Step 1 ($$|x| \geq 5$$), the condition $$x \neq \pm 2$$ is automatically satisfied.
Requires $$x^2 + 2x - 15 > 0$$ (strictly positive for log).
Factoring: $$(x+5)(x-3) > 0$$.
By interval testing: positive when $$x < -5$$ or $$x > 3$$.
From Step 1: $$x \leq -5$$ or $$x \geq 5$$.
From Step 3: $$x < -5$$ or $$x > 3$$.
Intersection: $$(x \leq -5) \cap (x < -5) = x < -5$$, and $$(x \geq 5) \cap (x > 3) = x \geq 5$$.
Wait: at $$x = -5$$: $$x^2 + 2x - 15 = 25 - 10 - 15 = 0$$, and $$\log(0)$$ is undefined. So $$x = -5$$ is excluded.
Domain: $$(-\infty, -5) \cup [5, \infty)$$.
Comparing with $$(-\infty, \alpha) \cup [\beta, \infty)$$: $$\alpha = -5$$ and $$\beta = 5$$.
$$\alpha^2 + \beta^3 = (-5)^2 + 5^3 = 25 + 125 = 150$$.
The correct answer is Option C: 150.
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