How to figure out absolute value 4/6-8/ what is the answer

If it's 4|6-8|, the answer would be 8
6-8=-2 but since its absolute value it would just be 2
4×2=8

X^2 - 4x +(4/2^2) + y^2 + 8y + (8/2^2) = -4 + (4/2^2) + (8/2^2)(x + 2)^2 + (y + 4)^2 = -4 + 4 + 16your center is (-2, -4) and the radius is the sqrt of -4 + 4 + 16 which is 4