# Math Help - factoring

1. ## factoring

can someone tell me how to factor this?
(x-3)(x-1)(x+1)(x+3)+64
thanks.

2. Originally Posted by 21_knip
can someone tell me how to factor this?
(x-3)(x-1)(x+1)(x+3)+64
thanks.
If you expand and simplify (and there's an easy way to do this by hand) you get $x^4 - 10x^2 + 73$.

This can be factorised as two irreducible real quadratics factors and four complex linear factors otherwise.

3. is this the final answer when it is said to factor completely? ur answer, is it still factorable?

4. Originally Posted by 21_knip
is this the final answer when it is said to factor completely? ur answer, is it still factorable?
Is the quartic I have given yu to be factorised over real or complex numbers? Start by thinking how to factorise into two irreducible quadratics.

5. ## factoring

if i changed 64 to 16 what would be the answer?
(x-3)(x-1)(x+1)(x+3)+16

No. The quartic becomes $x^4 - 10x^2 + 25$ and this has a very simple factorisation (think perfect square) ....