happykiddo 2 years ago please show how to factor...... 28n^4+ 16n^3− 80n^2

1. amytincan

the smallest factor of the coefficients is 4, and the smallest factor of the n is n^2.

2. happykiddo

yeah i know and the answer is supposed to be 4n^2(7n-10) (n+2)..........but how do i get that after in factor out 4n^2 and factored further and have 4n^2(7n^2-10n+14n-20)

3. amytincan

okay backing up 4n^2(7n^2+4n-20) , working on the trinomial in the parentesis you need to find two numbers when multiplied equal -20 and when added equal 4. You have a coefficient in front of n^2, so you have to take that into consideration. A good thing to do is to take the factored answer and FOIL it to see how it turns into the trinomial inside the parenthesis

4. amytincan

(7n-10)(n+2) =7n^2+14n-10n-20 Do you see it?

5. happykiddo

where did the n+2 come from?

6. amytincan

its a factor of the trinomial. http://patrickjmt.com/factoring-trinomials-a-quadratic-trinomial-by-trial-and-error/

7. happykiddo

ok i'll check it out if i have questions may i ask you.

8. happykiddo

thanks for the help : )