diketahui persaman lingkaran x^2+y^+Ax-8y+15=0 melalui titik (-3,2). tentukan: a.nilai a b.pusat dan jari-jari tolong bantu jawab

a) x^2 + y^2 + Ax - 8y + 15 = 0
Melalui (-3,2)
(-3)^2 + (2)^2 + A(-3) - 8(2) + 15 = 0
9 + 4 - 3A - 16 + 15 = 0
-3A = -12
A = 4

b) x^2 + y^2 + Ax + By + C = 0
x^2 + y^2 + 4x - 8y + 15 = 0
Pusat (a,b) = (-1/2 A, -1/2 B) = (-1/2 . 4, -1/2 . -8) = (-2, 4)
Jari-jari = r = √(a^2 + b^2 - C) = √((-2)^2 + 4^2 - 15) = √(4 + 16 - 15) = √5