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’b’c’ are the coordinates to the new location of the transformed triangle abc. find the distance between the coordinates points to use for your calculations.