The Algebra Teacher\'s Guide to Reteaching Essential Concepts and Skills

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WORKSHEET 3.22: USING MATRICES — ADDITION,
SUBTRACTION, AND SCALAR MULTIPLICATION
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Matrices can be added, subtracted, or multiplied by a number called a scalar. Follow the
guidelines below:


  • Two matrices can be added or subtracted only if they have the same number of rows
    and columns. Add or subtract the corresponding elements.

  • To multiply a matrix by a scalar, multiply each element by the scalar.


EXAMPLES


A=

[

− 3 − 41

167

]

B=

[

− 176

248

]

A+B=

[

−43 7

31015

]

A−B=

[

− 2 − 11 − 5

− 12 − 1

]

4 A=

[

− 12 −16 4

42428

]

DIRECTIONS: Use these matrices to perform the indicated operations, if possible. If not
possible, write ‘‘impossible.’’

C=

[

− 34

68

]

D=

[

10

− 41

]

E=

[

01

38

]

N=




13

− 38

− 46



⎦ M=




16

73

49





  1. C+D 2. D+E 3. − 2 C 4. C−E
    5. N+E 6. 3 N 7. M−N 8. M+C


CHALLENGE:Is it possible to add three or more matrices? Explain your
reasoning.

131

Copyright


©


2011 by Judith A. Muschla, Gary Robert Muschla, and Erin Muschla. All rights reserved.

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