Math Help - Understanding Matrix Suffix Notation

1. Understanding Matrix Suffix Notation

I'm having trouble interpreting matrices represented in suffix notation. For example, I am given that the matrices A, B and x have elements a(ij) b(ij) and x(i) respectively. I then have to write down the matrix represented by

$\sum_{i,j}&space;a_{ij}&space;b_{kj}&space;x_{i}$
[Edit: Latex corrected]
How do I work out what this summation represents.

2. Originally Posted by StaryNight
I'm having trouble interpreting matrices represented in suffix notation. For example, I am given that the matrices A, B and x have elements a(ij) b(ij) and x(i) respectively. I then have to write down the matrix represented by

$\sum_{i,j}&space;x_{ij}&space;b_{kj}&space;x_{xi}$

How do I work out what this summation represents.
I don't think your notations are correct.

First of all, you have $a_{ij}$ and $x_i$ then where does this $x_{ij}$ come from?

Secondly, I don't know what $k$ represents in $b_{kj}$.

Lastly, the suffix in $x_{xi}$ too has no meaning.

3. Originally Posted by Sambit
I don't think your notations are correct.

First of all, you have $a_{ij}$ and $x_i$ then where does this $x_{ij}$ come from?

Secondly, I don't know what $k$ represents in $b_{kj}$.

Lastly, the suffix in $x_{xi}$ too has no meaning.
Apologies, I managed to make a couple of mistakes doing the Latex. I've corrected my original post.