# Solving Systems Of Linear Equations - HP 40gs User Manual

Graphing calculator.

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To divide by a
square matrix
To invert a matrix
To negate each
element

## Solving systems of linear equations

Example
18-8
For division of a matrix or a vector by a square matrix,
the number of rows of the dividend (or the number of
elements, if it is a vector) must equal the number of rows
in the divisor.
This operation is not a mathematical division: it is a left-
multiplication by the inverse of the divisor. M1/M2 is
–1
equivalent to M2
To divide the two matrices M1 and M2 that you created
for the previous example, press the following keys:
M1
M2
You can invert a square matrix in HOME by typing the
matrix (or its variable name) and pressing
. Or you can use the matrix INVERSE command.
Enter INVERSE(matrixname) in HOME and press
.
You can change the sign of each element in a matrix by
pressing
before the matrix name.
Solve the following linear system:
2x
+
3y
+
4z
=
5
x
+
y z
=
7
4x y
+
2z
=
1
1. Open the Matrix
catalog and create a
vector.
MATRIX
2. Create the vector of the
constants in the linear
system.
5
7
1
* M1.
–1
x
Matrices

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