Major error in Barron's Math II 8th edition:

kingsknight
Mon, 18 Jan 2010 13:25:43 +0000

4x^2+4y^2-12x-20y-2=0

4x^2+4y^2-12x-20y-2+9+25=9+25 (just add 9 and 25)

x^2+y^2-3x-20y-2/4+9/4+25/4=9/4+25/4 (divide everything by four)

x^2-3x+9/4+y^2-20y+25/4=9/4+25/4+2/4 (rearrange them and add 2/4 to both sides)

(x-2/3)^2+(y-5/2)^2=9 (factor out the left and add up the right)