Question

how do you factor this?
x^4-3x^2-4

Answer 1

Let x^2 = y,what do you get?

Answer 2

i get, (x^2-4)(x^2+1)
i dont think its right!

Answer 3

let y= x^2 then think of it as:

y^2-3y-4 then you have:

(y+1)(y-4)

so:

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

now keep factoring:

(x^2 +1)(x-2)(x+2)

Answer 4

Yes, you can further factorise (x^2 -4)

Answer 5

AHHHH! i just realized you could factor further! THANKS GUYS!