1. **Stating the problem:** Find the solution set of the equation $$x^2 = -9$$ where $$x \in \mathbb{R}$$. 2. **Formula and rules:** The equation $$x^2 = c$$ has real solutions only if $$c \geq 0$$ because the square of any real number is non-negative. 3. **Intermediate work:** Here, $$c = -9 < 0$$, so there is no real number $$x$$ such that $$x^2 = -9$$. 4. **Conclusion:** Therefore, the solution set in real numbers is the empty set $$\emptyset$$. 1. **Stating the problem:** The function $$f : \mathbb{R} \to \mathbb{R}$$ is defined by $$f(X) = 9$$. Find the point through which its graph passes when $$X=7$$. 2. **Explanation:** Since $$f(X) = 9$$ is a constant function, its graph is a horizontal line at $$y=9$$. 3. **Intermediate work:** At $$X=7$$, $$f(7) = 9$$. 4. **Conclusion:** The graph passes through the point $$(7, 9)$$.