Question

What is the determinant of A = [ -2 2 -5 4 -1 -2 1 3 -5]

Answer 1

-51

Explanation:

`\left[\begin{array}{ccc}-2&2&-5\\4&-1&-2\\1&3&-5\end{array}\right] =1*\left[\begin{array}{ccc}2&-5\\-1&-2\end{array}\right] +(-3)*\left[\begin{array}{ccc}-2&-5\\4&-2\end{array}\right] +(-5)*\left[\begin{array}{ccc}-2&2\\4&-1\end{array}\right] =-9+(-72)+30=-9-72+30=-51`

Answer 2

-51

Explanation:

`\begin{vmatrix}-2&2&-5\\4&-1&-2\\1&3&-5\end{vmatrix}=\\=\mathsf{-10-4-60-5+40-12}=\\=\mathsf{-91+40}=\\=\mathsf{-51}`