Solve polynomial inequality & graph on # line:

Question

melissa_something · Answer

attachment

melissa_something · Answer

If you can just show work I got u on the medal

saifoo.khan · Answer

Do you know how to solve a cubic equation/

melissa_something · Answer

No :/

saifoo.khan · Answer

http://www.youtube.com/watch?v=q2yHgVerzgc

melissa_something · Answer

That's so different from what am doing

mathteacher1729 · Answer

Are you allowed to use a graphing calculator for this problem or do they want you to factor it by hand?

melissa_something · Answer

Hand :'(

mathteacher1729 · Answer

Two ways to go about this.
 
1) Use the rational root theorem to find the roots and factor probably ending up with synthetic division.  (kinda lengthy process) 

2) Look at your choices and test your function at the places marked with "(" and ")" on the number lines. Use that info to find out where the zeros are and evaluate points in between to see if they're + or -.

melissa_something · Answer

Oh boy. I thought you had to factor first?

mathteacher1729 · Answer

You can actually eliminate two of the choices right off the bat... Note that since the order of the polynomial is 3 and the highest power x is positive, that means the function's y values go to +infinity as values of x get larger. |dw:1427737976526:dw| So find the choices that have (whatever, +infinity) as one of intervals.