Algebra 2 help-circles?

x^2 -2x + ___ +y^2 -4y + ___ = -1 + ___ + ___

x^2 -2x +1 +y^2 -4y +4 = -1 +1 +4

(x-1)^2 +((y-2)^2 =2^2

center (1,2) r=2

x^2 -8x +16 +y^2 +4y +4 = -11 +16 +4

(x-4)^2 +(y+2) = 9 = 3^2

center ( 4, -2) r=3

x²+y²-2x-4y+1=0

x²-2x + y²-4y = -1

[x²-2x + (-1)²] + [y²-4x + (-2)²] = -1+ (-1)² + (-2)²

(x-1)² + (y-2)² = 2²

center (1,2)

x²+y²-8x+4y+11=0

x²-8x + y²+4y = -11

[x²-8x + (-4)²] + [y²+4y + 2²] = -11 + (-4)² + 2²

(x-4)² + (y+2)² = 3²

radius = 3

The best way is to complete the squares for x and y to get the form (x-h)^2 + (y-k)^2 = r^2, where (h,k) is the center and r is the radius.

Excel is the best software do this in

Lotus 123 is better !