Chapter 11.5, Problem 23E

(a)

To determine

Whether the graph of the equation $x^2+2xy+y^2+x-y=0$ is a parabola, an ellipse or a hyperbola by discriminant.

(b)

To determine

To eliminate: The xy-term by the use of rotation axes from the conic $x^2+2xy+y^2+x-y=0$.

(c)

To determine

To sketch: The graph of $x^2+2xy+y^2+x-y=0$.