Matrix multiplication Definition and 106 Threads

Ok, maybe a dumb question, but anyway: if I have some matrices equation like this: AB = BC if I want to multiply both sides by some matrix Z can I stick it in the middle? AZB = BZC I know I can do these two: ABZ = BCZ ZAB = ZBC but can I do the middle too? Thanks!

I know how to solve basic problems like this, but I have no clue where to start with one of the first parts in this example. I am given the following information about C, which is a 2 X 2 matrix. C \left[ \begin{array}{cc} 1\\ 2 \end{array} \right] = \left[ \begin{array}{cc} 2\\ 1...

Is there an easy way to do 3 X 3 Matrix Multiplication?

For a computer program, I have to multiply: a[][] * b[] and store it in c[] how does the math for this work out on paper? What exactly am I multiplying?

I have homework due and no help from the TA's due to a language problem. How do you multiply a scalar with a matrix? It seems so simple, but I keep getting errors, such as "matrix must be square". .m funtion code: function X=parabola(a,x,b) X=(x*a+b)^2; Command window code ...

Why might two matrices commute? I.e Why would AB=BA because in general, matrices usually do not commute. What are the properties of matrices that do commute? Ben