Check the picture below.
[tex]\bf ~~~~~~\textit{parabola vertex form} \\\\ \begin{array}{llll} y=a(x- h)^2+ k\qquad \leftarrow \textit{let's use this one}\\\\ x=a(y- k)^2+ h \end{array} \qquad\qquad vertex~~(\stackrel{}{ h},\stackrel{}{ k}) \\\\[-0.35em] \rule{34em}{0.25pt}[/tex]
[tex]\bf \begin{cases} h=0\\ k=0 \end{cases}\implies y=a(x-0)^2+0 \\\\\\ \textit{we also know that } \begin{cases} x=14\\ y=-22 \end{cases}\implies -22=a(14-0)^2+0 \\\\\\ -22=a(14)^2\implies -22=196a\implies \cfrac{-22}{196}=a\implies -\cfrac{11}{98}=a \\\\[-0.35em] ~\dotfill\\\\ y=a(x-0)^2+0\implies \boxed{y=-\cfrac{11}{98}x^2}[/tex]
