We proceed as in the hints. We factor the left hand side in as
.
Since , the ring of integers here is given by which is a unique factorization domain. We compute the greatest common divisor of the terms on the left hand side.
Let , the ideal generated by these two elements. Now notice that in the equation , if x is even, then modulo 8 considerations show that and this is a contradiction since the only odd square is 1 modulo 8. Thus, x is odd and so y is even.
We may further suppose that these factors are coprime for otherwise, if a prime p divides both x and y, then it must divide 11 and hence must equal 11. Rewriting the equation would then give
or simplified
and hence 11 divides 1 which is a contradiction. So y is even and x and y are coprime. Further, we have that
and that
Hence and thus, the two elements are coprime. Thus, we may write
where above, the right hand side absorbs the units since (and we relabeled the values) where .
Expanding and comparing coefficients yields
or simplified
The second equation tells us that since it must be a factor of 8. Checking these 8 values shows that only or gives admissable values. This leads to the points
or
The first point gives and the second point yields . These correspond to the given points and thus complete the problem.
|