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

http://latex.codecogs.com/gif.downlo...j}&space;x_{i}

[Edit: Latex corrected]

How do I work out what this summation represents.