FERMAT 2020 Problem 22

Suppose that x and y are real numbers that satisfy the two equations:

\begin{aligned} x^2+3 x y+y^2 & =909 \\ 3 x^2+x y+3 y^2 & =1287 \end{aligned}

What is a possible value for x+y ?

Answer Choices
A. 27
B. 39
C. 29
D. 92
E. 41