Question

Dadas as matrizes A e B  determinante  A+ B, é:




A=$\left[\begin{array}{ccc}1&2\\5&4\\\end{array}\right]$
Dadas as matrizes A e B  determinante  A+ B, é:


B=
$\left[\begin{array}{ccc}-2&-2\\0&1\\\end{array}\right]$

Answer 1

Mano,

use a regra para determinante de 2 ª ordem, já que trata-se de determinantes:

$A+B= \left|\begin{array}{ccc}1&2\\5&4\\\end{array}\right|+ \left|\begin{array}{ccc}-2&-2\\0&1\\\end{array}\right|~~~~~~~.\\\\\\ A+B=[(1\cdot4)-(2\cdot5)]+[(-2\cdot1)-(-2\cdot0)].\\\\ A+B=[4-10]+[-2+0]\\\\ A+B=-6+(-2)\\\\ A+B=-6-2\\\\ \Large\boxed{\boxed{A+B=-8}}.\\.$

Portanto, alternativa D.

Tenha ótimos estudos manoo