ACT Math : Scalar interactions with Matrices

Study concepts, example questions & explanations for ACT Math

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Example Questions

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Example Question #11 : Matrices

Define matrix , and let  be the 3x3 identity matrix.

If , evaluate .

Possible Answers:

The correct answer is not given among the other responses.

Correct answer:

Explanation:

The 3x3 identity matrix is 

Both scalar multplication of a matrix and matrix addition are performed elementwise, so

 is the second element in the second row, which is 6; similarly, . The equation becomes

Example Question #12 : Matrices

 

Possible Answers:

 

 

Correct answer:

 

Explanation:

When multiplying a constant to a matrix, multiply each entry in the matrix by the constant.

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