I need help with Polynomial functions p(x) Algebra 2

Here is the Directions...

Write the polynomial function of least degree with integral foefficients that has the given zeroes.
( or in other words as my teacher says for a simpler explanation, find the P(x) )

I know how to get the functions for the zeroes, but i just don't know how to get the final answers..
here are the problems ( do as much as you please, but i really need help on them... )

1. 6, 2i

2. i, -5i

3. 4, -1, -3i

4. 1 + 2i, 1 - i

1. 6, 2i
If 2i is a zero then -2i is a zero too because complex zeros come in conjugate pairs that way.
Use the factor theorem to convert the three zeros into factors:
(x - 6) (x - 2i) (x + 2i)
Multiply the factors together (It's easiest to multiply the two complex factors together first, then the real one.):
x^3 - 6x^2 + 4x - 24

Exactly the same steps for all the rest.

2. i, -5i
i, -i, -5i, 5i
(x - i) (x + i) (x + 5i) (x - 5i)
x^4 + 26x^2 + 25

3. 4, -1, -3i
4, -1, -3i, 3i
(x - 4) (x + 1) (x + 3i) (x - 3i)
x^4 - 3x^3 + 5x^2 - 27x - 36

4. 1 + 2i, 1 - i
1 + 2i, 1 - 2i, 1 - i, 1 + i
(x - 1 - 2i) (x - 1 + 2i) (x - 1 + i) (x - 1 - i)
x^4 - 4x^3 + 11x^2 - 14x + 10