# Math Help - Matrix multiplication

1. ## Matrix multiplication

I need some guidance here...

How do I multiply these three?

I only know how to multiply when it looks like this...

But I cant figure out how to do with the one above. Plz help

2. Originally Posted by sf1903
I need some guidance here...

How do I multiply these three?

I only know how to multiply when it looks like this...

But I cant figure out how to do with the one above. Plz help
Remember that $ABC = (AB)C = A(BC)$. So you can either first multiply the first two and then multiply the result by the third, or first multiply the last two and then multiply the result by the first.

3. Hi,

$\begin{pmatrix} 1 & 2 \end{pmatrix} \times \begin{pmatrix} 3 & 2\\ -1 & 0 \end{pmatrix}=\begin{pmatrix} 1 & 2 \end{pmatrix}$

Then you keep this result and multiply with the last matrix:

$\begin{pmatrix} 1 & 2 \end{pmatrix} \times \begin{pmatrix} 2 \\ 2 \end{pmatrix}=6$