how much did polly pay for her pie ingredients

Yep....good job!!!

Now....just perform the multiplication of the two matrices

 [ You should end up with the last answer in the resulting 3 x 1 matrix  ]

is the result for the 3 * 1 matrix the answer for #2?

To calculate the cost of Polly's ingredients

[ 2 2 5 4 ]  [ 3]

                   5              =   [ (2(3) + 2(5) + 5(2) + 4(6) ] =  [ 6 + 10 + 10 + 24] =  [ 50]

                   2

                  [6]

Notice that this is the last entry in  the matrix  [ 37  ]

                                                                           92

                                                                         [  50 ]

To get the cost of  Patricia's ingredients  we would have

[ 6 6 4 6 ] [ 3 ]

                  5       

                  2

                [ 6 ]            The result of this should be 92   [the second entry]

And finally, the cost of Pauline's ingredients is

[ 3 4 1 1 ] [ 3]

                  5

                  2

                [6 ]        The result of this should be 37  [the first entry ]

Does this make sense ?????

yes sir thank you !