I'm aweful at Completing the square I don't know why but I am. I have a problem that requires me to do so and show my work. When I was done I did the same problem using the Quadratic Formula and the answers don't match. Can someone help?

Problem: 9x^2+36X+31

Here is my work Lemme know if you can see my mistake:

Completing the Square:

x^2+4x=-31/9 (Rearranged and divided by 9)

x^2+4x+4=-31/9+36/9 (Half of the coefficent, squared and added to both sides)

(x+2)^2=5/9 (simplified)

x+2 = +-sqrt(5)/3

x= -2+-sqrt(5)/3

Quadratic

-36+-sprt(1296-4*9*31)/2(9)

-36+-sqrt(180)/18

-36+-6sqrt(5)/18

x= -6+-sqrt(5)/3

Thanks