Question

x^4 + x^2 - 20
Help! I have no clue how to factor this! Do i have to square root everything?

Answer 1

(x^2 + 5)(x^2 - 4)

If you set y = x^2 and look at the original as:
y^2 + y - 20
It should factor easily to
(y + 5)(y - 4)
which equals:
(x^2 + 5)(x^2 - 4)

Answer 2

so would the final answer be (x^2 + 5)(x^2 - 4) or (y + 5)(y - 4) ???

Answer 3

The final answer is
(x^2 + 5)(x^2 - 4)

If you multiply that, you will get your original equation.