The Vertex of a Parabola Occurs Where the Derivative of Its

The vertex of a parabola occurs where the derivative of its equation is 0, so an equation associated with the equation of a
parabola can be solved to find the x-coordinate of the vertex. Find the vertex of the parabola, given the equation of the
parabola and its associated equation.
-Equation of parabola: $f ( x ) = 3 x - x ^ { 2 }$ ; associated equation: $0 = 3 - 2 x$

A) $\left( \frac { 3 } { 2 } , - \frac { 9 } { 4 } \right)$
B) $\left( - \frac { 3 } { 2 } , - \frac { 9 } { 4 } \right)$
C) $\left( \frac { 3 } { 2 } , \frac { 9 } { 4 } \right)$
D) $\left( - \frac { 3 } { 2 } , \frac { 9 } { 4 } \right)$