Wrong results for "Large" simultaneous equation calculation

[David Parman]

I am new to Octave, and ran into a problem with my first real application. I am working with a large (120x120) set of simultaneous equations. When I solve the equations using the A\b nomenclature, I get an answer - no complaints from Octave. But the answer is clearly very wrong - all of the values are about 6 or more orders of magnitude smaller than they should be. I have the same set of calculations in MathCad, which yields an appropriate solution. I can also approximate the solution using direct analytical approach, which also confirms that the Octave result is way off. 

I found a couple of examples online for this type of solution (small 2x2 and 3x3 examples, one of which had the wrong answer on the webpage - confirmed by Octave and MathCad). These all worked just fine, but they have "nice" values (some of my values can be very large numbers, on the order of 10^18).

I have spot checked the matrices and the values appear to be exactly the same in Octave as they are in MathCad. Does anybody have an idea what I might be missing here?

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"The cost of a thing is the amount of life which is required to be exchanged for it" -- Thoreau