Question: how to rref on ti 89?
Answer: Reduced row-echelon form (rref) can be obtained on the TI-89 in one step by using rref(matrix). To enter rref(, press CATALOG button (Row 3 Column 3), followed by s (key 3) and then use the up arrow to select rref(. Press ENTER button to place rref( on the command line.