Chapter 8, Problem 90RE

To determine

To solve: the system of linear equations.

Answer to Problem 90RE

The solution of system is $x=5$ and $y=6$ .

Explanation of Solution

Given information:

Given equation

  $\{\begin{array}{l}x+3y=23\\ -6x+2y=-18\end{array}$

Calculation:

Consider system of linear equations,

  $\{\begin{array}{l}x+3y=23\\ -6x+2y=-18\end{array}$

Write the system in matrix form $AX=B$ ,

  $\left[\begin{array}{cc}1& 3\\ -6& 2\end{array}\right]\left[\begin{array}{l}x\\ y\end{array}\right]=\left[\begin{array}{l}23\\ -18\end{array}\right]$

Multiply $A^{-1}$ on both sides of equation $AX=B$ . Thus

  $X=A^{-1}B$

Press 2^nd MATRIX of calculator and select EDIT option. Select option $\left[B\right]$ by pressing ‘2’

  

Enter matrix parameter as follows:

  

Press 2^nd QUIT

Press 2^nd MATRIX of calculator and select NAMES option. Select option $\left[B\right]$ by pressing ‘2’

  

Enter matrix parameter as follows:

  

Press 2^nd QUIT

Type $\left[A^{-1}\right]\left[B\right]$ and press ENTER

  

The solution of system is $x=5$ and $y=6$ .