What is the coeffiicient of x^2 y^2 in the expansion of (x + y)^4 + (x + 3y)^4?

C(4,2) ( x)^2 (y)^2     =   6x^2y^2

C(4,2)   ( x)^2  ( 3y)^2  =  6x^2 * 9y^2  =  54x^2y^2

(6 + 54) x^2 y ^2  = 

60 x^2y^2