TI-83 Resource Website
The RREF (reduced row echelon form) is a very effective way for solving a system of equations using matrices.
NOTE: Please enter the matrices before proceeding with this example. If you are not sure how to enter matrices, complete the Entering a Matrix module.
Example: Use RREF to solve a system of equations that can be represented by the following matrix:
Note that the first column of the matrix has the coefficients of x, the second column has the coefficients of y, and the last column has the constants.
Step 1: Press MATRX.
On the TI-83, the MATRX button is one down and to the right from the green ALPHA button
On the TI-83 Plus/84, press the 2nd button, then MATRX (above the X-1 key)
Using the right arrow, go to the MATH menu. Use the down arrow button to select "B:rref( ".
Step 2: Press ENTER. "rref(" will appear on the home screen.
Step 3: Press MATRIX again. Select the matrix by using the down arrows and highlighting the matrix you want. In this example, Matrix A is selected (1: is highlighted).
Step 4: Press ENTER. "rref([A])" will appear on the home screen.
Step 5: Press ENTER. The resulting matrix will appear on the right side of the screen. The solution of the system is displayed in the right hand side column. For this example, x = 3 and y = -1.
This site was last updated 10/07/05 and is maintained by Donna L. Sperry