Please see the attachment.
Let E = (See attachment) and let A be an arbitrary 3x3 matrix.
a. Describe the rows of EA in terms of the rows of A
b. Describe the columns of AE in terms of the columns of A
( 1 0 0 ) (a_11 a_12 a_13) ( a_11 a_12 a_13 )
EA = ( 0 1 0 ) (a_21 a_22 a_23) = ( a_21 a_22 a_23 )
This solution shows the effect of left and right multiplication by a simple matrix on the rows and columns of the original matrix.