what is the sum of the roots of the polynomial shown below f(x)=3x^3+12x^2+3x-18

Question

marissalovescats · Answer

Well first thing you wanna go is factor this.

The 1st rule of factoring is looking for a GCF in all the terms. 

Do you see a GCF here?

anonymous · Answer

3?

marissalovescats · Answer

Good now take out 3 and what does your polynomial simplify to?

anonymous · Answer

what do you mean by take out three?

marissalovescats · Answer

Like this |dw:1373389401771:dw|

Then you simplify the inside (basically divide every term by 3)

anonymous · Answer

so it would be x^3+4x^2+x-6 ?

marissalovescats · Answer

Unfortunately, I realize now your problem did not want us to pull out the GCF because then we cannot factor by grouping (which is weird I've never seen that)

Okay so go back to the original equation we are going ot factor by grouping. Have you ever heard of that??

anonymous · Answer

i have heard of it but i dont know quite understand how to do it

marissalovescats · Answer

|dw:1373389809674:dw|

This is factor by grouping. We group the 2 terms together and you pull out a GCF of both and after you do that, you should have the same binomial inside the parentheses.