http://www.ck12.org Chapter 9. Conics
8.y^2 + 2 y− 8 x+ 33 = 0
9.x^2 − 8 x+ 20 y+ 36 = 0
10.x^2 + 6 x− 12 y− 15 = 0
11.y^2 − 12 y+ 8 x+ 4 = 0
12.x^2 + 6 x− 4 y+ 21 = 0
13.y^2 + 14 y− 2 x+ 59 = 0
14.x^2 + 12 x−^83 y+^923 = 0
15.x^2 + 2 x−^45 y+ 1 = 0