Respuesta :

By applying inverse of a matrix, we find that the solution of the system of linear equations is (x, y) = (5/7, - 2/7).

How to solve a system of equation with inverse matrices

In linear algebra, systems of linear equations with a unique solution can be represented by the following expression:

[tex]\vec A \cdot \vec x = \vec B[/tex]      (1)

Where:

  • [tex]\vec A[/tex] - Matrix of dependent constants.
  • [tex]\vec x[/tex] - Vector column of variables.
  • [tex]\vec B[/tex] - Vector column of independent constants.

The solution of such systems is defined by:

[tex]\vec x = \vec A^{-1}\cdot \vec B[/tex]

[tex]\vec x = \frac{1}{\det(\vec A)}\cdot adj\left(\vec A\right) \cdot \vec B[/tex], where [tex]\det \left(\vec A\right) \ne 0[/tex].

Where:

  • [tex]\det \left(\vec A\right)[/tex] - Determinant of the matrix of dependent constants.
  • [tex]adj \left(\vec A\right)[/tex] - Adjoint of the matrix of dependent constants.

For the case of [tex]\vec A \in \mathbb{R}_{2\times 2}[/tex], the inverse of [tex]\vec A[/tex] is:

[tex]\vec A^{-1} = \frac{1}{\det \left(\vec A\right)} \cdot \left[\begin{array}{cc}a_{22}&-a_{12}\\-a_{21}&a_{11}\end{array}\right][/tex]     (2)

If we know that [tex]\vec A = \left[\begin{array}{cc}3&4\\5&2\end{array}\right][/tex] and [tex]\vec B = \left[\begin{array}{cc}1\\3\end{array}\right][/tex], then the solution of the system of linear equations is:

[tex]\vec A^{-1}= \frac{1}{(3)\cdot (2) - (5) \cdot (4)}\cdot \left[\begin{array}{cc}2&-4\\-5&3\end{array}\right][/tex]

[tex]\vec A^{-1} = -\frac{1}{14}\cdot \left[\begin{array}{cc}2&-4\\-5&3\end{array}\right][/tex]

[tex]\vec A^{-1} = \left[\begin{array}{cc}-\frac{1}{7} &\frac{2}{7} \\\frac{5}{14} &-\frac{3}{14} \end{array}\right][/tex]

[tex]\vec x = \left[\begin{array}{cc}-\frac{1}{7} &\frac{2}{7} \\\frac{5}{14} &-\frac{3}{14} \end{array}\right] \cdot \left[\begin{array}{cc}1\\3\end{array}\right][/tex]

[tex]\vec x = \left[\begin{array}{cc}\frac{5}{7} \\-\frac{2}{7} \end{array}\right][/tex]

By applying inverse of a matrix, we find that the solution of the system of linear equations is (x, y) = (5/7, - 2/7).

To learn more on inverse of matrices: https://brainly.com/question/4017205

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