Question

I just need to know the net ionic equation and balance them. I figured the equation. but the net and balance is harder.

Fe(NO3)3 (aq) + Na2CO3 (aq) = FeCO3 (s) + Na2(NO3)3 (aq)

Fe(NO3)3 (aq) + NaI (aq) =FeI (s) + Na(NO3)3 (aq)

Ba(NO3)3 (aq) + Na3PO4(aq) = BaPO4 (s) + Na3(NO3)3 (aq)

Answer 1

Here is how you do them.
solids are written as the molecule.
aq are written as the ions.
gases as molecules
weak electrolytes (weak acids, weak bases, water) as molecules.
Then cancel ions common to both sides.

However, before you begin that you must learn how to write and balance the equation. I will do the first one for you. REMEMBER THIS. After you write the formula you may NOT change the subscripts I can tell that you are trying to balance the equation at the time you write the equation. These are two separate steps.
You may be transcribing a word equation to a chemical equation. Write those as a separate post and we can try to get things right at the beginning.