can anybody explain me these two statements? Any reference to read? Thanks

[Bal23]

a=-w**2;

a=x`[1,2];

[Reeza]

IML Operators
http://support.sas.com/rnd/app/iml/matrix.html

Base SAS operators

http://support.sas.com/documentation/cdl/en/lrcon/62955/HTML/default/viewer.htm#a000780367.htm

** is Exponentiation

` is transpose for a matrix

[Rick_SAS · Accepted solution]

The first statement is equivalent to 

a = -w*w;

which is matrix multiplication.

The second statement is equivalent to 

a = x[2,1];

because transpose means flip the matrix across the main diagonal.

It sounds like you have some very basic questions about the SAS/IML language. You might want to look at these resources to help you get started with the language: "Ten tips for learning the SAS/IML language."