+1993 
if you could check this ne as well, wasnt sure what to put at the bottom, if you could help with that ?thank you again, this is the last three
+128460 First one
-9 is correct
Second one
-3R2 + 4R1 .....as before......I assume that the result goes in R1
-3R2 = -24 3 -9
4R1 = -12 20 8
___________
-36 23 -1
So.....the resulting matrix is
-36 23 -1
8 1 3
+128460 The second one is easier if we identify what the parts of each martix represent
The first matrix
S M L
[ 1.50 2.50 6.50 ] prices of the three sizes at store 1
[ 2.00 3.50 8.00 ] prices of the three sizes at store 2
The second matrix
No. on shelf No. in stockroom
of each size of each size
10 24 S
18 48 M
6 12 L
The first row of the first matrix x the first column of the second gives the total price of the stock on the shelves in store 1....so this is entry a11 in the resulting matrix =
(1.50)(10 ) + (2.50)*(18) + (6.50)(6) = 99
The first row of th first matrix x the secolumn of the second matrix gives the total price of the stock in the stockroom at store 1....this is entry a12 in the resulting matrix =
(1.50)(24 ) + (2.50)(48) + (6.50)(12) = 234
The second row of the first matrix x the first column of the second matrix gives the total price of the stock on the shelves at store 2......this is entry a21 in the resulting matrix =
(2.00)(10) + (3.50)(18) + (8.00)(6) = 131
Finally.....second row of the first matrix x second column of the second matrix gives the total price of the stock in the stockroom of store 2.....this is entry a22 in the resulting matrix =
(2.00)(24) + (3.50)(48) + (8.00)(12) = 312
So we have the following resultant (product) matrix :
Shelves Stockroom
99 234 Store 1
131 312 Store 2
The rows represent the different stores
And the columns represent the location of the stock within each store
