Recent content by Tonia1

I still don't understand how the 2nd cofactor is -6. This is what I did: -/-2 1 (top row) 4 1 (bottom row)/ = -[(-2)(1) - (4)(1)] = -[-2 -4] = -(-6) Why is the answer supposed to be -6 instead of positive 6? the two negatives should make it positive.

Okay, thanks. For some reason, I was thinking that the bars were like an absolute value sign, but it's not the same.

Why does your example show that the first cofactor must be negative even though the answer in the book says positive 2? I do not know why I did not get positive 2 for the first cofactor, or positive 4 for the 3rd cofactor. I followed your explanation and got this for the 1st cofactor: I crossed...

Find the cofactors of the elements in the second row of every determinant: $$\begin{vmatrix}-2 & 0 & 1 \\ 1 & 2 & 0 \\ 4 & 2 & 1 \end{vmatrix}$$ I am going to guess that I need to look at each number in the second horizontal row to see what i and j are for finding the cofactors of the elements...