Question

Resolva:
$\left[\begin{array}{ccc}1+ \sqrt{5} &3\\4&1- \sqrt{5} \end{array}\right]$ =

Answer 1

$Resolu\c{c}\~ao \to \left\{\begin{array}{ccc} \left[\begin{array}{ccc}1+\sqrt{5}&3\\4&1-\sqrt{5}\end{array}\right] \\\\D = (1+\sqrt{5})(1-\sqrt{5}) - (3)*(4)\\\\D = 1^2-(\sqrt{5})^2 - 12\\\\D = 1-5 - 12\\\\\boxed{\boxed{D = -16 }}\end{array}\right$

Espero ter ajudado. =^.^=