Solve for the roots in the equation below. x4 + 3x2 - 4 = 0

Step-1 : Multiply the coefficient of the first term by the constant 1 • - 4 = - 4

Step-2 : Find two factors of - 4 whose sum equals the coefficient of the middle term, which is 3.

-4 + 1 = - 3 - 2 + 2 = 0 - 1 + 4 = 3 That's it

Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, - 1 and 4

x4 - 1x2 + 4x2 - 4

Step-4 : Add up the first 2 terms, pulling out like factors:

x2 • (x2-1)

Add up the last 2 terms, pulling out common factors:

4 • (x2-1)

Step-5 : Add up the four terms of step 4:

(x2+4) • (x2-1)

Which is the desired factorization