[tex] \bf \textit{vertex of a vertical parabola, using coefficients}
\\\\
y=\stackrel{\stackrel{a}{\downarrow }}{-3}x^2\stackrel{\stackrel{b}{\downarrow }}{+6}x\stackrel{\stackrel{c}{\downarrow }}{-4}
\qquad \qquad
\left(-\cfrac{ b}{2 a}~~~~ ,~~~~ c-\cfrac{ b^2}{4 a}\right)
\\\\\\
\left(-\cfrac{6}{2(-3)}~~,~~-4-\cfrac{6^2}{4(-3)} \right)\implies \left(1~~,~~-4+\cfrac{36}{12} \right)
\\\\\\
(1~~,~~-4+3)\implies (1~,-1) [/tex]
