What is the radius of a circle whose equation is x2 y2 - 10x 6y 18 = 0?

Given the equation of a circle" x^2 + y^2 - 4x + 6y - 36 = 0 We will use completing the square method to rewrite the equation into the form: (x-a) ^2 + (y-b) ^2 = r^2 where (a, b) is the center and r is the radius. Let us rewrite the terms.==> x^2 - 4x + y^2 + 6y = 36Now we will complete the square for both x^2 ands y^2. We will add [ (coefficient of x) / 2]^2 and [ (coefficients of y) / 2]^2 to both sides. Then we will add : (4/2) ^2 = 2^2 = 4 (6/2) ^2 = 3^2 = 9Then we will add 4 and 9 to both sides.==> x^2 - 4x + 4 + y^2 + 6y + 9 = 36 + 4 + 9==> (x-2) ^2 + (y+3) ^2 = 49==> (x-2) ^2 + (y+3) ^2 = 7^2Now we will compare the equation withe the standard form of a circle. Then we conclude that: The center of the circle is: (2, - 3) and the radius is 7.