I have no idea how to do this

Question

Find the equation of the circle that passes through the point P(8, -2) and whose center is the point C(4, 1). Then sketch its graph

Answer 1

from the center, you know the equation is

(x-4)^2 + (y-1)^2 = r^2

Now just plug in your point, which lies on the circle:

(8-4)^2 + (-2-2)^2 = r^2
r^2 = 32, so

(x-4)^2 + (y-1)^2 = 32