Question

Sendo
A = 2 1 3
1 -1 2
-2 1 -1
Então o det A é:

a)8

b)-8

c)0

d)10

e)-10

Answer 1

Resposta:

$\textsf{Leia abaixo}$

Explicação passo-a-passo:

$\mathsf{ A=\begin{array}{|c c c|}\sf2&\sf1&\sf3\\\sf1&\sf-1&\sf2\\\sf-2&\sf1&\sf-1 \end{array}}\begin{array}{c c}\sf2&\sf1\\\sf1&\sf-1\\\sf-2&\sf1 \end{array}$

$\mathsf{det(A)= (2+(-4)+3)-(-1+4+6)}$

$\mathsf{det(A)=(2-4+3)-9 }$

$\mathsf{ det(A)=1-9}$

$\boxed{\boxed{\mathsf{det(A)=-8}} }\leftarrow \textsf{Letra B}$