Part A complete day/dx=?Part B The ellipse has two horizontal tangents. Find an equation of the lower one.The lower horizontal tangent line is defined by the equation y=?Part C c. The ellipse has two vertical tangents. Find an equation of the leftmost one.The leftmost vertical tangent line is defined by the equation x=?Part D d. Find the point at which the leftmost vertical tangent line touches the ellipse.The leftmost vertical tangent line touches the ellipse at the point?

The graph of the equation x2 + xy + y' = 7 is an ellipse lying obliquely in the plane, as illustrated in the figure below