So the row operations I was given are :
1) E2 => -2E2
2)E1 <-> E3
So i did calculate the determinant of matrix B as 6
But i really cant find any resource on how det(B) relates to det(-B). That's where I am having issues. I know that [-B] is the negation of all the elements in [B], but I am having a hard time joining that with the concept of determinants. I couldn't find any examples online about this either. Nor does my textbook have anything that seems helpful.