下面是一道关于抛物线的SAT数学题及其解法的内容，非常详细。SAT题中，抛物线是必考的一类，虽然中学课程都有所涉及，还是相对比较抽象，尤其是在理解SAT数学题的表达方式上。下面我们来看看这道关于抛物线的SAT数学题吧。

　　Read the following SAT test question and then click on a button to select your answer.

　　The quadratic functionis graphed in the-plane above. If　for all values of, which of the following could be the coordinates of point?

　　Answer Choices

　　(A)

　　(B)

　　(C)

　　(D)

　　(E)

　　The correct answer is C

　　Explanation

　　The fact thatfor all values ofmeans that the pointis the maximum of the quadratic function, somust be the vertex of the parabola. The parabola intersects the-axis at the pointsand, somust be halfway betweenand. Therefore,. Of the choices, the only one with-coordinate equal tois. Therefore,could be the coordinates of point.

(编辑：Joe)