Respuesta :

Aivi
if u do the math u woud get something like this:

...x^6 + ...x^5y + ...x^4y^2 + ... x^3 y^3 +... x^2 y ^4 + ... x y^5 + ... y^6 

so 4th term need to have x^3 y^3 
then its 4320x^3y^3