Question

find the center and radius of circle x²+y²-4x-6y+9=0​

Answer 1

Answer:

To find the radius of the circle you must complete the squares in x and y.

x^2+y^2–4x+6y-12 = 0, or

x^2–4x+4 + y^2+6y+9 -4–9–12 = 0, or

x^2–4x+4 + y^2+6y+9 = 12+9+4 = 25, or

(x-2)^2 + (y+3)^2 = 5^2.

So the centre of the circle is (2,-3) and the radius is 5. Answer.