Question

How do you multiply matrices `((2,3), (1, -3))` and `B=((-1, 0, 2), (0, 2, 3))`?

Answer 1

(see below)

Explanation:

Remember that the row from the first factor times
the column from the second factor
is used to generate the row-column entry of the product.

`color(blue)(((2,3),(1,-3)))xxcolor(red)(((-1,0,2),(0,2,3)))`

#=((color(blue)2xxcolor(red)((-1))+color(blue)3xxcolor(red)0, color(blue)2xxcolor(red)0+color(blue)3xxcolor(red)2, color(blue)2xxcolor(red)2+color(blue)3xxcolor(red)3), (color(blue)1xxcolor(red)((-1))+color(blue)((-3))xxcolor(red)0, color(blue)1xxcolor(red)0+color(blue)((-3))xxcolor(red)2, color(blue)1xxcolor(red)2+color(blue)((-3))xxcolor(red)3))#

`=((-2,6,13),(-1,-6,-7))`