An equation is like a mystery thriller;
it grips you once you've begun it.
You are the sleuth who stalks the killer;
X represents whodunit.

The scene of the crime must first be cleared,
the suspects called into session,
the cross-examination geared
to wring from X a confession.

If the case is baffling and hard to crack,
a grilling with Newton or Horner
will put you on the proper track,
and X will be trapped in a corner.