The distance of any point which lies on the circumference of the circle from the centre of the circle is called radius.

∴ OA = OB = Radius of given Circle

taking square on both sides, we get-

OA² = OB²

⇒ (-1-2)² + [y-(-3y)]² = (5-2)² + [7-(-3y)]²

[using distance formula, the distance between points (x₁,y₁) and (x₂,y₂) is equal to units.]

⇒ 9 + 16y² = 9 + (7 + 3y)²

⇒ 16y² = 49 + 42y + 9y²

⇒ 7y² - 42y - 49 = 0

⇒ 7(y²-6y-7) = 0

⇒ y²-7y + y-7 = 0

⇒ y(y-7) + 1(y-7) = 0

⇒ (y + 1)(y-7) = 0

∴ y = 7 or y = -1

Thus, possible values of y are 7 or -1.