SOLUTION: Factor: x^4-13x^2+4 (I do not know how to put this on a formula plotting system so this is the best way for me to ask the question). **I tried to use the integral factor th

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Factor: x^4-13x^2+4 (I do not know how to put this on a formula plotting system so this is the best way for me to ask the question). **I tried to use the integral factor th      Log On


   

Question 536920: Factor:
x^4-13x^2+4 (I do not know how to put this on a formula plotting system so this is the best way for me to ask the question).
**I tried to use the integral factor theorem to find the factors of 4 and see which one makes the above equal to zero and go from there. But none of those factors make it equal to zero. So how would I factor this expression?
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
I would expect that this problem was meant to say factor x%5E4-13x%5E2%2B40
In that case, since you know that y%5E2-13y%2B40=%28y-8%29%28y-5%29
your first step would be
x%5E4-13x%5E2%2B40=%28x%5E2-8%29%28x%5E2-5%29
From there on it does not get too pretty
%28x%5E2-5%29=%28x%2Bsqrt%285%29%29%28x-sqrt%285%29%29 and

So you could say

However it gets much uglier with x%5E4-13x%5E2%2B4.
The solutions to y%5E2-13y%2B4=0
are
They are both positive, so we would end up with