Operation Manual

Chapter 10: Matrices 147
Getting Started: Systems of Linear Equations
Getting Started is a fast-paced introduction. Read the chapter for details.
Find the solution of X + 2Y + 3Z = 3 and 2X + 3Y + 4Z = 3. On the TI-84 Plus, you can solve a system of
linear equations by entering the coefficients as elements in a matrix, and then using
rref( to obtain the
reduced row-echelon form.
1. Press y. Press ~~ to display the
MATRX EDIT
menu. Press
1 to select 1: [A].
2. Press
2 Í 4 Í to define a 2×4 matrix. The
rectangular cursor indicates the current element. Ellipses
(
...) indicate additional columns beyond the screen.
3. Press
1 Í to enter the first element. The rectangular
cursor moves to the second column of the first row.
4. Press
2 Í 3 Í 3 Í to complete the first row for
X + 2Y + 3Z = 3.
5. Press 2 Í 3 Í 4 Í 3 Í to enter the second
row for 2X + 3Y + 4Z = 3.
6. Press y5 to return to the home screen. If necessary,
press ‘ to clear the home screen. Press y~ to
display the
MATRX MATH menu. Press } to wrap to the end
of the menu. Select
B:rref( to copy rref( to the home screen.
7. Press y
1 to select 1: [A] from the MATRX NAMES
menu. Press ¤Í. The reduced row-echelon form of the
matrix is displayed and stored in
Ans.
1X N 1Z = L3 therefore X = L3+Z
1Y + 2Z = 3 therefore Y = 3 N 2Z