Answer
See image:
.
Work Step by Step
Divide with 4,
$\displaystyle \frac{z}{4}=\frac{x^{2}}{2^{2}}+\frac{y^{2}}{1^{2}}$
Compare with Table 11.1 and conclude that this is an elliptical paraboloid.
The traces in xz and yz planes are parabolas.
The trace in planes parallel to the xy plane are ellipses.
