I. Menu Keys  Keys that offer choices
I. MATRX (matrix)
The matrix menu is quite extensive and an exhaustive study here is beyond the scope of this tutorial. However, once you have learned what is presented here, you should have enough basic knowledge to use the remainder of the menu.
When you first access the MATRIX menu the screen that appears has the names of matrices.
NAMES

MATH

EDIT

1. The NAMES menu is used to paste the name of a matrix into the home screen or a program.
2. The MATH menu contains all of the operations that can be done with a matrix.
3. The EDIT menu is where you set the size of the menu and enter the elements.
The example below will take you through the basic steps of entering a matrix and using it to solve a system of equations, which is one of the main applications of matrices that you will use in an algebra course.
Example: Use a matrix to solve the following system of equations.
To use a matrix to solve a system of equations, you put the matrix in reduced row echelon form. While this can be a tedious and time consuming process to do by hand, the TI83 will do this in one step.
Go to MATRIX and EDIT.


Define [A] to be a 3X4 matrix.
Use the cursor and the ENTER key to move through the spaces. 

Now enter the coefficients
and constants from the system by entering the value and pressing ENTER. 

Return to the home screen
( ) and access the MATRIX MATH menu and scroll down to item B. 

Hit ENTER to return
to the home screen. 

Enter matrix [A]
by pressing 1 and close the parentheses. 

Press ENTER and
read the solution as x=2, y=1, z=4. 
Matrices can be entered directly into the home screen by using the [ ] keys which are accessed by entering and . You enter [ to start the matrix and then enclose each row in [ ] and close the matrix with ]. Below are some screens showing some manipulations with matrices.