Answer these factoring polynomial questions

You don't need to explain it... I just need answers to compare mine to. Thanks.
1) 3x^4 - 48x^2
2) m^4 - m^2 - 20
3) x^3 - 5x^2 - x + 5
4) xy - 4xz + 12y - 48z

1) 3(x-4)(x+4)x^2

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

3) (x-5)(x-1)(x+1)

4) xy - 4xz + 12y - 48z