Find all points $\displaystyle {\left({x},{y}\right)}$ on the graph of the equation $\displaystyle -{3}{x}^{{2}}-{2}{y}^{{4}}=-{8}{x}-{4}{y}^{{2}}$ where the tangent line is:

(a)  horizontal:

(b)  vertical:           

Round to the nearest hundredth for each coordinate.