Math , Circle - Conic Sections

Question

Find the equation of a circle with a y-intercept and x-intercept of -1 and which contains the point (0,2).

Answer 1

(x-1/2)^2 + (y-1/2)^2 = 5/2

use the general formula for a circle, (x-h)^2 + (y-k)^2 = r^2

plug in each of the 3 points to get 3 equations. With 3 equations 3 unknowns solve for h,k and r

by substitution and elimination.