[tex]\bf \qquad \qquad \textit{vertex of a parabola}\\\quad \\\begin{array}{llccll}
f(x)=&3x^2&-24x&+51\\
&\uparrow &\uparrow &\uparrow \\
&a&b&c
\end{array}\qquad
\left(-\cfrac{{{ b}}}{2{{ a}}}\quad ,\quad {{ c}}-\cfrac{{{ b}}^2}{4{{ a}}}\right)[/tex]