Back again

For those who didn't see earlier thread I'll just put this first

we can write a, b & c like this:

Proof:

let a=194, b=142 and c=170

using (1)-(2) we have

substituting this in (1), (2) & (3) gives the expected results

All good so far but...

let a=527, b=289, c=425

using (1)-(2) we have

substituting this in (1), (2) & (3) gives

What am I doing wrong or misunderstanding?

Many thanks

Pro