Question

Me ajude 30PTS URGENTE- Considere a matriz A=
Segue foto::

Answer 1

Ok, vamos lá.

Matriz A = $\left[\begin{array}{ccc}2&4&6\\0&2&12\\1&3&18\end{array}\right]$

Matriz B = $\left[\begin{array}{ccc}4&8&2\\0&2&2\\1&3&3\end{array}\right]$

DetA = $\left[\begin{array}{ccc}2&4&6\\0&2&12\\1&3&18\end{array}\right] \[\begin{array}{ccc}2&4\\0&2\\1&3\end{array}\right]$

Diagonal principal:

$2*2*18 = 72$
$4*12*1=48$
$6*0*3=0$

Soma:

$72+48+0= 120$

Diagonal secundária:

$6*2*1=12$
$2*12*3=72$
$4*0*18=0$

Soma: $12+72+0=84$

DetA = $120-84 = 36$


Agora vamos para a b)

DetB=$\left[\begin{array}{ccc}4&8&2\\0&2&2\\1&3&3\end{array}\right] \begin{array}{ccc}4&8\\0&2\\1&3\end{array}\right]$

Diagonal principal:

$4*2*3=24$
$8*2*1=16$
$2*0*3=0$

Soma: $24+16+0=40$

Diagonal secundária:

$2*2*1=4$
$3*2*4=24$
$3*0*8=0$

Soma: $4+24+0 = 28$

DetB = $40-28=12$

Espero ter ajudado :) Abraço