a parabola intersects the x - axis at x = 3 and x = 9. what is the x - coordinate of the parabolas vertex?

Explanation:

Step1: Recall vertex - x - coordinate property

The x - coordinate of the vertex of a parabola is the mid - point of the x - intercepts.

Step2: Use mid - point formula

The mid - point formula for two points (x_1) and (x_2) is (x=\frac{x_1 + x_2}{2}). Here (x_1 = 3) and (x_2=9). So (x=\frac{3 + 9}{2}).

Step3: Calculate the value

(\frac{3+9}{2}=\frac{12}{2}=6).

Answer:

6