Question

pergunta sobre matriz

Answer 1

Olá,

$\left[\begin{array}{cc}3&-1\\1&3\end{array}\right] . \left[\begin{array}{cc}x\\y\end{array}\right] =4\left[\begin{array}{cc}1\\2\end{array}\right] \\ \\ \\ \left[\begin{array}{cc}3&-1\\1&3\end{array}\right] . \left[\begin{array}{cc}x\\y\end{array}\right] =\left[\begin{array}{cc}4\\8\end{array}\right] \\ \\ \\ \left[\begin{array}{cc}3x-y\\x+3y\end{array}\right] =\left[\begin{array}{cc}4\\8\end{array}\right]$

$\left \{ {{3x-y=4} \atop {x+3y=8}} \right. \\ \\ \left \{ {{3x-y=4(3)} \atop {x+3y=8}} \right. + \\ \\ 9x+x-3y+3y=12+8 \\ 10x=20 \\ \\ x=2 \\ \\ \\ 3x-y=4 \\ y=3x-4 \\ y=3.2-4 \\ y=6-4 \\ \\ y=2$

∴ x + y = 2 + 2 = 4

Tenha uma boa noite!