College Algebra (6th Edition)

Foci: $(0, -4\sqrt{2})$ and $(0,4\sqrt{2}).$
Major axis parallel to the $y$-axis, vertical. $a^{2}=81,$ $a=9$ $b^{2}=49,$ $b=7$ Vertices: $(h, k-a),\quad (h, k+a)$ $(0, -9),\quad (0, 9)$ Foci are $c$ units above and $c$ units below the center, $c^{2}=a^{2}-b^{2}=81-49=32$ $c=\sqrt{32}=4\sqrt{2}$ Foci: $(0, -4\sqrt{2})$ and $(0,4\sqrt{2}).$