If [ -2 5 7 6] and |B| = -|A|, which matrix is matrix B?

Question

asked Jul 4, 2022 59.7k views

1 Answer

Ghasem Ramezani · Answer 1 · 2022-07-10T18:00:21+0000

|A| and |B| denote the determinants of the matrices A and B.

We have

$|A| = \begin{vmatrix}-2&5\\7&6\end{vmatrix} = (-2)*6-7*5 = -12 - 35 = -47$

Then B is a matrix such that |B| = -|A| = +47.

The only choice satisfying this is C, since

$\begin{vmatrix}12&1\\13&5\end{vmatrix} = 12*5-13*1 = 60 - 13 = 47$