## Precalculus (6th Edition) Blitzer

The expression is X=\left[ \begin{align} & \,\,5 \\ & \,\,4 \\ & -1 \\ \end{align} \right].
Consider the system equations, \begin{align} & x-y=1 \\ & 6x+y+20z=14 \\ & y+3z=1 \end{align} The linear system can be written as, $AX=B$ $\left[ \begin{matrix} 1 & -1 & 0 \\ 6 & 1 & 20 \\ 0 & 1 & 3 \\ \end{matrix} \right]\left[ \begin{matrix} x \\ y \\ z \\ \end{matrix} \right]=\left[ \begin{matrix} 1 \\ 14 \\ 1 \\ \end{matrix} \right]$ The solution is given by $X={{A}^{-1}}B$; consequently, we must find ${{A}^{-1}}B$ by using a graphic calculator. We will follow the steps given below: (1) Select the matrix $A$ from the matrix edit menu and then enter or accept the dimensions. Next, select the matrix $B$ and enter the elements in the matrix. (2) Use ${{2}^{nd}}$ and press the matrix button. (3) Select the matrix $A$ and use the enter button and then use the function ${{X}^{-1}}$ for multiplication of the matrix. (4) Then use the ${{2}^{nd}}$ button and press the matrix button or select matrix $B$ and press the enter button. (5) Press the enter button to get the value of ${{A}^{-1}}B$. Therefore, X=\left[ \begin{align} & 5 \\ & 4 \\ & -1 \\ \end{align} \right]