kmekme100
Oct 4, 2009, 03:13 PM
factor fully
f(x) = x^4 - 5x^2 + 4
galactus
Oct 4, 2009, 05:05 PM
Let u=x^{2}
Then, we get u^{2}-5u+4
Now, factor the quadratic and resub.
u^{2}-5u+4=(u-4)(u-1)
Since u=x^{2}, resub:
(x^{2}-4)(x^{2}-1)
Note the difference of two squares in both.
(x+2)(x-2)(x+1)(x-1)