For Z(x) = x6 - 6x5 - 7x4 + 50x3 - 46x2 - 24x + 72, Descartes' Rule gives positive-real-zero possibilities 4, 2, or 0 and negative-real-zero possibilities 2 or 0. A student claims the graph shows 2 positive real zero(s) and 2 negative real zero(s). Which comparison is correct?
