It has come to my attention that I would have made a 382.  In other words, it looks like I made 3 mistakes, one of which is just an additional answer to a problem.
 

#23: sqrt(2916)

my answer: 58   correct answer: 54

 

#49: 1/(2+bi) = a + bi, then a is ___________

my answer: 4/29   correct answer: 2/29

 

#66: Find x, 0 <= x <= 10, if 3x = 13(mod 7)

my answer: 2     correct answer: 9 or 2

 

Okay, so I am not perfect, but I bet a 382 would score pretty high among everyone!!!