\(\dfrac{x^2}{a^2} + \dfrac{y^2}{b^2} + \dfrac{z^2}{c^2}=1 \)
\(\dfrac{x^2}{a^2} + \dfrac{y^2}{b^2} - \dfrac{z^2}{c^2}=1 \)
\(\dfrac{x^2}{a^2} + \dfrac{y^2}{b^2} - \dfrac{z^2}{c^2}= -1 \)
\(\dfrac{x^2}{a^2} + \dfrac{y^2}{b^2} = z \)
\(\dfrac{x^2}{a^2} - \dfrac{y^2}{b^2} = z \)
\(\dfrac{x^2}{a^2} + \dfrac{y^2}{b^2} = \dfrac{z^2}{c^2} \)