Which quadratic equation is equivalent to (x – 4)2 – (x – 4) – 6 = 0? (u – 4)2 – (u – 4) – 6 = 0 where u = (x – 4) u2 – (u – 4) – 6 = 0 where u = (x – 4) u2 – 16 – u – 6 = 0 where u = (x – 4) u2 – u – 6 = 0 where u = (x – 4)