Determine the intervals on which the polynomial is entirely negative and those on which it is entirely positive. (Enter your answers using interval notation. Enter EMPTY or ∅ for the empty set.) −x^2 + 6x − 10I don't understand how to factor this, as as such, I can't figure out how to answer the question. Please help!

This is a parabola that opens downward.
Remember that the axis of symmetry is located at x=-b/(2a).
So the vertex is at (3,-1)
So functions slope is positive or increasing on (-co, 3] and decreasing on [3,co).