For instance: y=7.1428571428571
I found that if x=2.651277205434809, then the result of the equation will be 7.142856989730508 which makes it easily precise enough judging from the description. My app sent then a post request x=2.651277205434809 and I got code 200 response but the level isn't passed, the page I got didn't even have any error.
My code shouldn't have any problems with passing the answer, I used a very similar code to work on other chall sites.
What am I doing wrong?
Did it say your answer was wrong or just that it wasn't fast enough?
The thing is that in the response page I don't get either... I'm trying to find a problem with my output connection but can't really find anything wrong, I'm using POST method with x=(answer) as an output to the http://halls-of-valhalla.org/challenges/timed/timed2.php ofc with my PHPSESSID cookie as a request property.
Try looking at the content of the response after your post. If it says "You must be logged in order to submit an answer" on the page then there's a issue with your logging in. Otherwise it should give an error message saying that you took too long or that the answer was wrong. If it says none of those then maybe you're missing a field in your post.