Question 12425
 B =
 [-1  6 3 ]
 [ 2  0 5]
 [ 3  2 1]
 You did a good job and the answer is correct.

 But, wy not expanding along the 2nd row ,since it contains 0.
 det(B) = -2(6-6) - 5(-2 -18) = 100

 Also,you typed too many redundant 0's and repetitive det(B) in
 your solution. Such as
 det B = -1(0-10) - 6(2-15) + 3(4 - 0) 
 It seems that you don't have enough confdence in yourself.
 [Try to use your eyes and mind to calculate small numbers
 instead of using pen, or other tools.]
 
 I am a very lazy person,that is why I am always looking for the
 shortest cut to solve the problems.

 Kenny