(a - b)^2 x^2 - 4abx - (a-b)^2
solve for x by factorisation method.
The problem is an old one. You have not copied it correctly. It should be
then it can be factored.
In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.