Question

How do you find the zeroes of `f(x) = x^4 -24x^2- 25`?

Answer 1

`x^4-24x^2-25`

`=(x^2-25)(x^2+1)`

`=(x-5)(x+5)(x^2+1)`

`x^2+1 > 0` for all `x in RR`

So the only zeros are given by `x = -5` and `x = 5`.