19. Conic Sections

Sketch a graph of the circle based on the following equation: $x^2+\left(y-1\right)^2=9$

Sketch a graph of the circle based on the following equation: $\left(x-2\right)^2+\left(y+3\right)^2=1$

Find the equation for the following circle:

Determine if the equation $x^2+y^2-2x+4y-4=0$ is a circle, and if it is, find its center and radius.