ok I read the attached...but i could not understand what you want to know...
what do you need help with???
or did you just want someone to check your work??
This is an online class I am taking; (which I would not recommend to anyone, take the class in a traditional setting) check my work, give me the anwers, it doesn't really matter. These are the only nine questions I can't answer. I just want to get them done. Call me lazy, whatever...some things just weren't meant for people to understand and I think algebra is it for me.
If you multiply out the factors the leading lerm is x^3. This dominates
when |x| is large. So as x-> -inf f(x) ->-inf, and as x->inf f(x)->inf.
Also f(x)=0 has three roots: 4, 0, -1. So
f(x)<0, when x<-1,
f(x)>0, when -1<x<0,
f(x)<0, when 0<x<4,
f(x)>0, when x>4
So f(x)>0 on (-1,0)U(4,inf)