Question

Comppete the equation X^2+y^2-10x+6y=15

Answer 1

I believe you meant:  Use completing the square to determine the center and radius of the circle represented by this equation:   X^2+y^2-10x+6y=15

x^2 - 10x + 25 - 25 + y^2 + 6y + 9 - 9 = 15
Then:
     (x-5)^2               +   (y+3)^2            = 24   = 2sqrt(6)

This circle is centered at (5,-3) and has radius 2sqrt(6).