x225+y216=1\frac{x^{2}}{25}+\frac{y^{2}}{16}=125x2+16y2=1
x225−y216=1\frac{x^{2}}{25}-\frac{y^{2}}{16}=125x2−16y2=1
x216−y236=1\frac{x^{2}}{16}-\frac{y^{2}}{36}=116x2−36y2=1
x29−y24=1\frac{x^{2}}{9}-\frac{y^{2}}{4}=19x2−4y2=1