Answer:
363C
Explanation:
V = KT and T = V/K
3.5=k(35+273) = 308k
k=3.5/308 =0.011
new T=7.0/0.011=636K = 636-273 =363C
Well, a compound has a total charge of 0. So, it's electrically neutral. Since the X is 3+ and the Y is 3- they add to 0. Meaning no subscripts are necessary. Why don't you try a different combo?
Like:
A^3 and B^1-, to get a 3- charge you need 3xB^1- so the formula is AB3
Does this help?