Question

Resolva os sistemas aplicando a regra de Cramer:
a) x+y=12
     3x-y=20

​

Answer 1

Resposta:

(4,8)

Explicação passo-a-passo:

$\left \{ {{x+y = 12} \atop {3x - y = 20}} \right. \\\\\\D = \left[\begin{array}{cccc}1&1\\3&1\end{array}\right]\\\\D = 1-3 = -2\\\\\\\\X = \left[\begin{array}{cccc}12&1\\20&1\end{array}\right]\\\\Dx = 12 - 20 = -8\\\\\\\\Y = \left[\begin{array}{cccc}1&12\\3&20\end{array}\right]\\\\Dy = 20 - 36 = -16\\\\\\\\x = \frac{Dx}{D} = \frac{-8}{-2} = 4\\\\y = \frac{Dy}{D} = \frac{-16}{-2} = 8$