Question 158789
multiplication is row times column 
__ the rows of the 1st matrix must have the same number of elements as the columns of the 2nd matrix


multiply the pairs of elements and add the products to find the element in the product matrix
__ row m multiplied by column n will give element m,n in the product matrix


1,1 __ 5*4+3*0 __ 20
1,2 __ 5*2+3*1 __ 13
1,3 __ 5*(-1)+3*3 __ 4
2,1 __ 0*4+1*0 __ 0
2,2 __ 0*2+1*1 __ 1
2,3 __ 0*(-1)+1*3 __ 3


[20  13  4]
[0   1   3]