Select all of the following that are quadratic functions. x = 3y2 – 6y + 5 y + 3 = –2 x 2+ 5 y = 2 x 2 – 8 x + 6 y= –7 x – 4 y – 3 x = 4 x 3 – x2 + 9 y = 5 x(x + 9) – 8 y – 2 x 2 = 3 x – 2 x 2 + 4