The vertex of the quadratic function $$ f(x) = -3(x - 4)(x +...

Question Analysis
This question evaluates the student's ability to determine the x-coordinate of the vertex of a quadratic function given in intercept/factored form.

Key Concept Explanation
The x-coordinate of the vertex of a quadratic function in intercept/factored form is the same as the axis of symmetry, which is given by .

Step-by-step Solution
1. Identify the x-intercepts: From , we have