Question

Help :/ find all the roots by factoring or using the quadratic formula.. f(x)=x^4+5x^2+4

Answer 1

To find the roots, we set f(x) = 0.
\(x^4 + 5x^2 4 = 0\)
Now, at first glance, this does not appear to be a quadratic equation. However, what happens if we made a substitution like u = x^2 ?

Answer 2

oops, that should say
\(x^4 + 5x^2 + 4 = 0\)

Answer 3

ok

Answer 4

I'm stuck here...l

Answer 5

(4x^2) (4x^2-1)

Answer 6

with u= x^2
u^2 +5u +4 =0

Answer 7

^ Yep. In this form, it becomes a quadratic equation!
So, now we are able to either factor or use quadratic formula with this equation.