Question

alguém consegue resolver esse problema de matriz na 2?

Answer 1

$A^2= \left[\begin{array}{ccc}3&-1\\x&y\end{array}\right]. \left[\begin{array}{ccc}3&-1\\x&y\end{array}\right] =\left[\begin{array}{ccc}9-x&-3-y\\3x+xy&-x+y^2\end{array}\right] \\ \\ \\ I^2=I \\ \\ \left[\begin{array}{ccc}9-x&-3-y\\3x+xy&-x+y^2\end{array}\right]=\left[\begin{array}{ccc}1&0\\0&1\end{array}\right] \\ \\ \\ 9-x=1 \\ \\ -x=1-9 \\ \\ x=8 \\ \\ -3-y=0 \\ \\ y=-3 \\ \\ |xy|=|8.(-3)|=|-24|=24$

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