We have to find the parameter a of a quadratic equation knowing the following
• The vertex is (3,-6).
,• A random point is (-7,14).
Based on the given information, we have the following
[tex]\begin{gathered} h=3 \\ k=-6 \\ x=-7 \\ y=14 \end{gathered}[/tex]The vertex form of a quadratic equation is
[tex]y=a(x-h)^2+k[/tex]Replacing all the givens, we have
[tex]14=a(-7-3)^2-6[/tex]Now, we solve for a
[tex]\begin{gathered} 14=a(-10)^2-6 \\ 14=a(100)-6 \\ 14+6=100a \\ 100a=20 \\ a=\frac{20}{100}=\frac{1}{5} \end{gathered}[/tex]