Q. 24. Which function represents a quadratic function whose graph has a range of {y∣y≥3} ?(A) f(x)=x2−6x+3(B) f(x)=x2−3(C) f(x)=x2+3(D) f(x)=x2+6x+3
Identify Vertex Form: Identify the vertex form of a quadratic function, which is y=a(x−h)2+k, where (h,k) is the vertex.
Analyze Option A: Analyze option (A): f(x)=x2−6x+3. Complete the square to find the vertex form. f(x)=(x2−6x+9)−9+3=(x−3)2−6. Vertex is (3,−6).
Analyze Option B: Since the vertex (3,−6) indicates the minimum point and the parabola opens upwards (a>0), the range is y∣y≥−6. This does not match y∣y≥3.
Analyze Option C: Analyze option (B): f(x)=x2−3. This is already in vertex form with vertex (0,−3).
Analyze Option D: The vertex (0,−3) shows the minimum point, and the parabola opens upwards. The range is y∣y≥−3. This does not match y∣y≥3.
Analyze Option D: The vertex (0,−3) shows the minimum point, and the parabola opens upwards. The range is y∣y≥−3. This does not match y∣y≥3. Analyze option (C): f(x)=x2+3. This is in vertex form with vertex (0,3).
Analyze Option D: The vertex (0,−3) shows the minimum point, and the parabola opens upwards. The range is {y∣y≥−3}. This does not match {y∣y≥3}. Analyze option (C): f(x)=x2+3. This is in vertex form with vertex (0,3). The vertex (0,3) indicates the minimum point, and the parabola opens upwards. The range is {y∣y≥3}. This matches the required range.
Analyze Option D: The vertex (0,−3) shows the minimum point, and the parabola opens upwards. The range is y∣y≥−3. This does not match y∣y≥3. Analyze option (C): f(x)=x2+3. This is in vertex form with vertex (0,3). The vertex (0,3) indicates the minimum point, and the parabola opens upwards. The range is y∣y≥3. This matches the required range. Analyze option (D): f(x)=x2+6x+3. Complete the square to find the vertex form. f(x)=(x2+6x+9)−9+3=(x+3)2−6. Vertex is (−3,−6).
Analyze Option D: The vertex (0,−3) shows the minimum point, and the parabola opens upwards. The range is y∣y≥−3. This does not match y∣y≥3. Analyze option (C): f(x)=x2+3. This is in vertex form with vertex (0,3). The vertex (0,3) indicates the minimum point, and the parabola opens upwards. The range is y∣y≥3. This matches the required range. Analyze option (D): f(x)=x2+6x+3. Complete the square to find the vertex form. f(x)=(x2+6x+9)−9+3=(x+3)2−6. Vertex is (−3,−6). Since the vertex (−3,−6) indicates the minimum point and the parabola opens upwards, the range is y∣y≥−31. This does not match y∣y≥3.
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