Sketch a graph of the surface. Z = 2 - x^2 - y^2.
Describe it in words.
A bowl opening to the left with a vertex at (2, 0, 0).
A bowl opening to the right with a vertex at ( - 2, 0, 0).
A bowl opening upwards with a vertex at (0, 0, 2).
A bowl opening downwards with a vertex at (0, 0, 2).
A bowl opening upwards with a vertex at (0, 0, - 2).