How do i complete the square for this equation ? x^2+ 8x+y^2-2y=64

Simplifying x2 + 8x + y2 + -2y = 64
 Reorder the terms: 8x + x2 + -2y + y2 = 64 Solving 8x + x2 + -2y + y2 = 64 Solving for variable 'x'.
 Reorder the terms: -64 + 8x + x2 + -2y + y2 = 64 + -64
  Combine like terms: 64 + -64 = 0 -64 + 8x + x2 + -2y + y2 = 0

 The solution to this equation could not be determined.

A. is the answer in this question