Matrices on the TI-83
10-1 in the TI-83 Guidebook

The TI series calculator performs numerous matrix operations. This example shows Gaussian Elimination.   The function rref is a easy way to find the reduce-row echelon form of any size matrix. (up to 99 rows)  It has many applications in this book.

Press matrx.jpg (1031 bytes) . Press arr_rt.jpg (776 bytes) arr_rt.jpg (776 bytes) to display the MATRX EDIT menu.  Press 1 to select 1:[A].    
Press 3 enter.jpg (983 bytes) 4 enter.jpg (983 bytes) to define a 34 matrix.  (3 rows, 4 columns)  The rectangular cursor indicates the current element.  Ellipses (...) indicate additional columns beyond the screen.  

We want to enter the coefficients into our matrix.
Press 3 enter.jpg (983 bytes) -6 enter.jpg (983 bytes) 9 enter.jpg (983 bytes) 0 enter.jpg (983 bytes) for the first row.
Press 4 enter.jpg (983 bytes) -6 enter.jpg (983 bytes) 8 enter.jpg (983 bytes) -4 enter.jpg (983 bytes) for the second row.
Press -2 enter.jpg (983 bytes) -1 enter.jpg (983 bytes) 1 enter.jpg (983 bytes) 7 enter.jpg (983 bytes) for the third row.

wpe158.jpg (3296 bytes)

Press 2nd.jpg (858 bytes) [QUIT] to return to the home screen.  If necessary press clear.jpg (1014 bytes) to clear the home screen.  
wpe164.jpg (2046 bytes) Press matrx.jpg (1031 bytes) arr_rt.jpg (776 bytes) to display the MATRX MATH menu.   Press arr_up.jpg (775 bytes) to wrap to the end of the menu.  Select B:rref . ( "reduced-row echelon form")  
wpe168.jpg (3421 bytes) Press matrx.jpg (1031 bytes) 1 to select 1:[A] from the MATRX NAMES menu. Press rt_par.jpg (777 bytes) enter.jpg (983 bytes) . The reduced-row echelon form of the matrix is displayed aand stored in Ans.

x = -3
y = 0
z  =  1