Determining Minimum Value of a Quadratic Function

Consider the function described by the equation:

$$f(x) = 3x^2 - 12x + 9$$.

Your task is to determine the value of $$x$$ for which the function has a minimum value. To find this value, you might consider using the vertex formula for a quadratic function, which is given by $$x = -\f\frac{b}{2a}$$, where $$a$$ and $$b$$ are the coefficients of the quadratic function in the form $$ax^2 + bx + c$$.