how do I solve these?

+4+ 4 x - Complete the square to find the general X - + equation for the circle. Identify the center and radius (no graph needed). x2+ y+4x-12y+15=0 r = Complete the square to find the general equation for the circle. Identify the center and radius (no graph needed). x2 + y2 + 10x -16y +53=0 r = Complete the square to find the general equation for the circle. Identify the center and radius ( no graph needed). x2 + 12 -2x +6y-15=0 c_ r =