Answer- A-16
Because when doing completing the square, you divide the coefficient of x by 2, which is 4, and the square it which is 16
A^2 + b^2 = c^2
6^2 + 8^2 = c^2
36 + 8^2 = c^2
36 + 64 = c^2
100 = c^2
√100 = c
10 = c
hope this helped, pls mark brainliest :)
