Solve x2 - 8x + 3 = 0 by completing the square.

which equation is used in the process?

(x - 4)2 = 0

(x - 4)2 = 13

(x - 4)2 = 19

The correct answer for this would be the second option. The equation that is used in the process in completing the square is this: (x - 4)2 = 13.
The solution is this:
(x-4)(x-4) = 13
x^2 - 4x - 4x + 16 = 13
x^2 - 8x +16 = 13
x^2 - 8x = 13 -16
x^2 - 8x = -3
x^2 - 8x + 3 = 0
Hope this answers your question. Have a great day!