On your TI-83 or 84 calculator, Press 2ND x-1 to get the MATRIX menu Scroll right to highlight EDIT Press ENTER Press 4 Press ENTER Press 5 Press ENTER Press 3 ENTER -2 ENTER 2 ENTER -1 ENTER 2 ENTER for the first row and ENTER after each of these on the other three rows: 4 1 1 6 8 -3 2 -2 1 5 5 0 3 -2 1 (pressing a 0 for the missing term in y on the 4th row. Press 2ND MODE (for QUIT to go to the main screen) Press 2ND x-1 to get the MATRIX menu again highlight MATH Scroll to B:rref Press ENTER Press 2ND x-1 to get the MATRIX menu again Press ENTER Press ) Press ENTER To make the decimals into fractions press MATH ENTER ENTER Scroll right and see that the matrix is 1 0 0 41/13 0 0 1 0 -9/13 0 0 0 1 -77/13 0 0 0 0 0 1 The bottom row 0 0 0 0 1 means this equation: 0x + 0y + 0z + 0w = 1 0 = 1, so the system is inconsistent. After all that, no solution exists! Phooey! Good thing we did it by calculator instead of by hand. That would have really been a let-down! :) Edwin