  In this paper we establish some results about the existence and precise forms
of finite order entire solutions of some systems of quadratic trinomial
functional equations one of which in $\mathbb{C}^n$, $n\in\mathbb{N}$ and other
two in $\mathbb{C}^2$. Our results are the generalizations and improvements of
the previous theorems given by Xu-Cao \cite{Xu & Cao & 2018,Xu & Cao & 2020}
and Xu-Jiang \cite{Xu Jiang RCSM 2022}. Moreover, we exhibit some examples in
support of our claims.
