simplify (x+y)(2x+y)+(x+2y)(x-y)

(x + y)(2x + y)+(x + 2y)(x-y)
[(x * 2x + y)+(y * 2x + y)]+[(x * x-y)+(2y * x-y)]
[2x² + xy + 2xy + y²]+[x²- xy + 2xy - 2y²]
2x² + 3xy + y² + x² + xy - 2y²
3x² + 4xy - y²