For question 17, a polynomial
can inly have a multiple root if there are any
-values for which
, using the multiple root theorem. If you attempt to solve the equation
, you should find it has only one solution,
. However,
and so the only potential multiple root isn't a root at all, and so there are no multiple roots.
In fact, if
is extended to an infinite polynomial, it is the polynomial version of
, as indicated by the fact that you then have
and thus there are no zeroes of
at all.