Algebra-1

Question Analysis
This question tests the student's understanding of the domain and range of a quadratic function in vertex form.

Key Concept Explanation
For any quadratic function, the domain is always all real numbers, . The range depends on the vertex's y-coordinate (k) and the sign of the coefficient a. If a < 0, the parabola opens downward, and the range is .

Step-by-step Solution
1. Identify the vertex form:

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