I do not know what you mean by "it" cancels out.
I also do not know for what values of x you are trying to calculate F(x).
Please show your work.
EG
F(0) = -0^3 - 0^2 + 6(0)
F(0) = -0 - 0 + 0
F(0) = 0
Therefore, one point on the graph has coordinates (0, 0).
In other words, this graph passes through the origin.