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

estrat1
Mon, 18 Jan 2010 13:09:54 +0000

No, I believe they have it right.

Divide both sides of the original by 4 to get: x^2 + y^2 - 3x - 4y - 2/4 = 0 (the reason they left it in the form of 2/4 is because, in completing the square, you have to add terms which have a denominator of 4…so 2/4 makes the whole equation look a little nicer).

Complete the square by adding 9/4 and 25/4 to both sides: (x^2 - 3x + 9/4) + (y^2 - 5y + 25/4) - 2/4 = 9/4 + 25/4

Simplify and take 2/4 to the right: (x-1.5)^2 + (y-2.5)^2 = 9/4 + 25/4 + 2/4 = 36/4 = 9