ELLIPSE

$$\frac{x^2}{4}+\frac{y^2}{9}=1$$

$$\frac{x^2}{16}+\frac{y^2}{9}=1$$

$$\frac{x^2}{16}+\frac{y^2}{16}=1$$

$$x^2+\frac{y^2}{49}=1$$

$$\left(-4,\ 0\right)\ and\ \left(4,\ 0\right)$$  

$$\left(0,\ -4\right)\ and\ \left(0,\ 4\right)$$  

$$\left(-5,\ 0\right)\ and\ \left(5,\ 0\right)$$  

$$\left(0,\ -5\right)\ and\ \left(0,\ 5\right)$$  

The center is  $$\left(0,0\right).$$  

The major axis is 81.

The minor axis is 4.

The graph is a horizontal ellipse.

$$\frac{x^2}{7}+\frac{y^2}{6}=1$$

$$\frac{x^2}{14}+\frac{y^2}{12}=1$$

$$\frac{x^2}{49}+\frac{y^2}{36}=1$$

$$\frac{x^2}{36}+\frac{y^2}{49}=1$$

$$\left(5,\ -4\right)\ and\ \left(5,\ 2\right)$$

undefined

$$\left(-1,\ -2\right)\ and\ \left(-1,\ 12\right)$$

$$\left(0,\ 0\right)\ and\ \left(2,\ 5\right)$$

$$\frac{x^2}{36}+\frac{y^2}{25}=1$$  

$$\frac{x^2}{25}+\frac{y^2}{36}=1$$  

$$\frac{x^2}{144}+\frac{y^2}{100}=1$$  

$$\frac{x^2}{100}+\frac{y^2}{144}=1$$