Answer
$${\left( {y - 6} \right)^2} = 8\left( {x + 2} \right)$$
Work Step by Step
$$\eqalign{
& {y^2} - 12y - 8x + 20 = 0 \cr
& {y^2} - 12y = 8x - 20 \cr
& {\text{Complete the square and factor}} \cr
& {y^2} - 12y + 36 = 8x - 20 + 36 \cr
& {\left( {y - 6} \right)^2} = 8x + 16 \cr
& {\left( {y - 6} \right)^2} = 8\left( {x + 2} \right) \cr
& {\text{The equation is in the form }}{\left( {y - k} \right)^2} = 4p\left( {x - h} \right) \cr
& \underbrace {{{\left( {y - 6} \right)}^2} = 8\left( {x + 2} \right)}_{{{\left( {y - k} \right)}^2} = 4p\left( {x - h} \right)} \to k = 6,{\text{ 4}}p = 8,{\text{ }}h = - 2 \cr
& 4p = 8,{\text{ }}p = 2 \cr
& {\text{The vertex of a parabola is}} \cr
& {\text{Vertex}}\left( {h,k} \right) \cr
& {\text{Focus }}\left( {p + h,k} \right):\left( {0,6} \right) \cr
& {\text{Directrix }}x = - p + h \cr
& x = - 4 \cr
& {\text{Graph}} \cr} $$
