Your code is badly written. First, it is way too long. Second, variables have meaningless names. Why you limit yourself to 3 by 3 systems, code for n by n system is not harder to write. Do you know about arrays in programming languages? If you really want code limited to 3 x 3 system, then it may be hard to find. OTOH code for n x n systems is easy to find. If you want Pascal code, there are "Numerical Recipes in Pascal" with code that used to be freely available on the net.
The code began as a parabolic curve fit program and that's why it's for 3 x 3 linear equations. However, the 3 x 3 program allows more view of the math operations and less view of a complex program structure. Then understanding the math operations would allow a more complex program for n x n systems to be written.
Much of the length of the program is the data input. It's a functioning program but not a fully developed program with looping input.
The present post just added some detail that was missed when converting the code from curve fit to solution of 3 x 3 linear equations.
The newsgroup has readers and the code is presented at an easy to understand level.