+1679 Find the vertex of the graph of the equation $x - y^2 + 8y = 13 + 2y + y^2 - 7y - 14$.
+1618
We can rewrite the equation as \begin{align*} x -y^2 + 8y &= 13 + 2y + y^2 - 7y - 14\ 2y^2 + 9y + x &= 0\ 2(y^2 + \tfrac{9}{2}y + \tfrac{x}{2}) &= 0 \ 0 &= (y+\tfrac{9}{4})^2 + x - \tfrac{81}{16} \end{align*}This is a parabola, opening upwards, with vertex at (1681,4−9).
