(x + 2y + 2) + (x + y + 2) + (2x + y + 4)
(x + 2y + 2) + (x + y + 2) + (2x + y + 4) collect like terms
[ x + x + 2x ] + [ 2y + y + y ] + [ 2 + 2 + 4 ] =
4x + 4y + 8
