Tentukan pusat dan jari jari lingkaran x2 + y2 - 6x - 2y - 6 = 0

x2 + y2 - 6x - 2y - 6 = 0
pusat (a, b)
= -1/2A , -1/2 B
= -1/2(-6) , -1/2(-2)
= 3, 1

jari jari
= √3*2 + 1*2 +6
= √16
= 4

jawab

Persamaan lingkaran
x^2 + y^2 - 6x - 2y - 6= 0
x² -6x + y² -2y = -6
(x - 3)² + (y +1)²  = - 6 + 9 + 1
(x - 3)² + (y +1)² = 4
p(3, -1)
r² = 4 --> r = 2