Question

solucione o sistema a seguir, utilizando a regra de cramer $\left \{ {{3x - 4y =1} \atop {x + 3y = 9}} \right.$

Answer 1

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$\left \{ {{3x - 4y =1} \atop {x + 3y = 9}} \right.$

$Det \left[\begin{array}{cc}3&-4&\\1&3\end{array}\right] =9+4=\boxed{13}$

$Det(x) \left[\begin{array}{cc}1&-4&\\9&3\end{array}\right] =3+36=\boxed{39}$

$Det(y) \left[\begin{array}{cc}3&1&\\1&9\end{array}\right] =27-1=\boxed{26}$

$x = \frac{Det(x)}{Det} \\ \\ x = \frac{39}{13} \\ \\ x=3$

$y = \frac{Det(y)}{Det} \\ \\ y = \frac{26}{13} \\ \\ y=2$

Logo, o valor de x = 3 e y = 2

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