Sketch a contour diagram of each function. Then, decide whether its contours are predominantly lines, parabolas, ellipses, or hyperbolas.

? Lines Parabolas Ellipses Hyperbolas  1. $z = x^2 - 2 y^2$

? Lines Parabolas Ellipses Hyperbolas  2. $z = x^2 + 5 y^2$

? Lines Parabolas Ellipses Hyperbolas  3. $z = y - 5 x^2$

? Lines Parabolas Ellipses Hyperbolas  4. $z = - 5 x^2$