Respuesta :

convert  to the standard form:-

x^2 + 14x + y^2 - 6y = -42

(x + 7)^2 - 49 + (y - 3)^2 - 9 = -42

(x + 7)^2 + (y - 3)^2 = -42 + 49 + 9 =  16

r^2 = 16 so r = 4 and the diameter = 2*4 = 8 Answer