Ans: D
It is given that the $y$-coordinate of the vertex of the graph of $y=f(x)$ is $7$. Hence, we have
It is given that the $y$-coordinate of the vertex of the graph of $y=f(x)$ is $7$. Hence, we have
$\begin{array}{rcl}
\dfrac{4(3)(k) – (-6)^2}{4(3)} & = & 7 \\
12 k – 36 & = & 84 \\
12k & = & 120 \\
k & = & 10
\end{array}$
