Use the matrices to find CD, if possible.

Question

Use the matrices to find CD, if possible. ​   ​

Quizplus · Accepted Answer

Let A = first matrix = 11ea984b_ae85_6b99_9029_6556ee6a93f3_TB4005_11
Let B = second matrix = 11ea984b_ae85_92aa_9029_4952708ccc08_TB4005_11

To find CD, we need to multiply A and B in the order CD (not DC as matrix multiplication is not commutative).

Multiplying A and B, we get:

A x B = 
[ 1 0 0 1 ] [ 1 1 2 1 ] = [ 2 1 2 2 ]
[ 0 1 1 0 ] [ 2 1 0 1 ]   [ 1 1 1 0 ]
[ 0 0 1 1 ] [ 1 2 1 0 ]   [ 1 1 1 1 ]
[ 0 1 0 0 ] [ 0 0 1 1 ]   [ 1 0 0 0 ]

So, CD = [ 2 1 2 2 ; 1 1 1 0 ; 1 1 1 1 ; 1 0 0 0 ]

The correct answer choice is D.

Use the Matrices to Find CD, If Possible