Question

What are the center and radius of the circle defined by the equation x^2 + y^2 -6x + 8y + 21=0

Answer 1

Explanation:

(x²-6x)+(y²+8y)=-21

(x²-6x+9)+(y²+8y+16)=-21+9+16

(x-3)²+(y+4)²=4

center=(3,-4),radius=√4=2