Texas Instruments TI-83 Plus Manual Book page 29

Now that you have completed the Getting Started example, you
can read further for more detailed instructions on how to use the
Simultaneous Equation Solver application. Some topics you
might want to explore are
•
Loading a matrix into the application
•
Storing data to a matrix
•
Displaying a matrix in reduced row-echelon form
TI-83 Plus Polynomial Root Finder / Simultaneous Equation Solver Application Page 29