Question

Tell whether the product CD is defined for C9x5 and D5x9. If yes, give the product's dimensions as the following example: 2x3. If no, write no in the box.

Answer 1

Tell whether the product BA is defined for A4x5 and B5x3. If yes, give the product's dimensions as the following example: 2x3. If no, write no in the box.

Answer 2

Tell whether the product SQ is defined for S4x5 and Q5x3. If yes, give the product's dimensions as the following example: 4x5. If no, write no in the box.

Answer 3

@Ashleyisakitty

Answer 4

the product will be defined when number of columns of 1st matrix = number of rows of 2nd.
and the resulting matrix will have number of rows same as 1st matrix and number of columns same as 2nd matrix.

Answer 5

example if X is 2X8 and Y is 8X4
then product XY will be defined and of dimension 2X4

Answer 6

@lissa_bug Attached are two matrix product study items form the site:
http://www.mathwarehouse.com/algebra/matrix/multiply-matrix.php

Answer 7

Thank you so much! I really get it now. :)

Answer 8

@lissa_bug You have three similar problems posted here so I will help you with the first one.

Tell whether the product CD is defined for C 9x5 and D 5x9.

Here's what my teacher said about this type problem. If the inner two numbers are the same (the 5 and the 5), then the matrices can be multiplied.
The dimensions of the product matrix will the the outer numbers (9 by 9).