SOLUTION: Perform the matrix operation, or if it is impossible, explain why. [1 2][1 -2 3] [-1 4][2 2 -1]

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Question 1129414: Perform the matrix operation, or if it is impossible, explain why.
[1 2][1 -2 3]
[-1 4][2 2 -1]

Found 2 solutions by Alex.33, greenestamps:
Answer by Alex.33(110) About Me  (Show Source):
You can put this solution on YOUR website!
Invalid operation.

Let me explain: When we are performing a multiplication of two matrices, the prerequisite is that we need to have equal number of (1)elements in each column of the first matrix, and (2)elements in the each row of the latter one.
And in our case, the number of (1) is 1, which is not equal to the number of (2), 3.
Hope it helps. Thanks! For more information about matrices please see here.

Answer by greenestamps(13203) About Me  (Show Source):
You can put this solution on YOUR website!


The answer from tutor @alex.33 is not right; he has the requirement backwards.

In multiplying matrices, the elements of the rows of the first matrix are multiplied one by one by the elements in the columns of the second matrix. So the requirement for being able to multiply two matrices is the the number of elements in each ROW of the FIRST matrix be equal to the number of elements in each COLUMN of the SECOND matrix.

Your example meets that requirement: there are 2 elements in each row of the first matrix and 2 elements in each column of the second.

The product matrix is

matrix%282%2C2%2C1%2C2%2C-1%2C4%29 * matrix%282%2C3%2C1%2C-2%2C3%2C2%2C2%2C-1%29 = = matrix%282%2C3%2C5%2C2%2C1%2C7%2C10%2C-7%29