Factorization problem 3x ^ 4 + 6x ^ 2-9

Factorization problem 3x ^ 4 + 6x ^ 2-9

3x^4+6x^2-9
=3(x^4+2x²-3)
=3(x²-1)(x²+3)
=3(x-1)(x+1)(x²+3)