Question

5. Aplicando a Regra de Cramer, encontre os valores dos determinantes para calcular x e y.

a) (1, -3)
b) (7 , 2)
c) (1, 2)
d) (-1,-2)

Answer 1

Resposta: x=1, y=2

Explicação passo-a-passo:

                                  $\left[\begin{array}{cc}1&2\\2&-3\\\end{array}\right] *\left[\begin{array}{c}x\\y\end{array}\right] =\left[\begin{array}{c}5\\-4\end{array}\right]$

Fazendo o determinante das matrizes abaixo:

$x=\;\frac{\left[\begin{array}{cc}5&2\\-4&-3\\\end{array}\right] }{\left[\begin{array}{cc}1&2\\2&-3\end{array}\right] }\;=\frac{-7}{-7}=1$

$y=\;\frac{\left[\begin{array}{cc}1&5\\2&-4\\\end{array}\right] }{\left[\begin{array}{cc}1&2\\2&-3\end{array}\right] }=\frac{-14}{-7}=2$