IMO Shortlist 2016 problem A6
Dodao/la:
arhiva3. listopada 2019. The equation
$$(x-1)(x-2)\cdots(x-2016)=(x-1)(x-2)\cdots (x-2016)$$is written on the board, with $2016$ linear factors on each side. What is the least possible value of $k$ for which it is possible to erase exactly $k$ of these $4032$ linear factors so that at least one factor remains on each side and the resulting equation has no real solutions?
Izvor: https://www.imo-official.org/problems/IMO2016SL.pdf