16. I am supposed to multiply the matrices B and C by each other B is:

Question

7 6

2 -3

-1 8

9 5

and C:

0 8

-2 1

Would someone mind showing me how to multiply CB? Thanks

~Saria

Answer 1

Oh god multiplying it by hand will take you FOREVER! If you have a graphing calculator, than its very easy. My teacher only taught us how to do it once, then she said just do it on the calculator from now on. The only way 2 matices can multiply with each other is if its dimensions have the same inner number. For example

3x2 2x3 the inner numbers are the same (2) so you can multiply it. If they are not the same, then there is no way to multiply it.

In your case, it is possible to multiply, But extremely long to explain, its way better to do it on the calculator. I think every teacher actually encourages students to do it using the calculator, it just saves time.