Phosphorus + iron(lll) oxide=tetraphosphorus decoxide + iron

Explanation:

Before writing this equation in a molecular equation form, let's identify each species:

phosphorus is a non-metal represented by 'P', it is solid at standard conditions;iron(III) oxide is an ionic compound consisting of iron(III) cations with a 3+ charge, as well as of oxide anions with a 2- charge, this means we may represent it as , which is also a solid material at standard conditions;tetraphosphorus decoxide consists of 4 phosphorus atoms and 10 oxygen atoms, as stated by the prefixes, this is also a solid;iron metal is simply 'Fe'.

Putting all of this into a single equation and balancing it, we obtain:

Yes you are correct use the scientific method