2x (2x + x)
9x^4y (2x + 5x^3)
8n (8n + 2n^2)
x^2 (x + 3)
5z^5y (3zy^2 - 6z^4 + 2zy)
7x (5x - 3x^2)
35x^2 - 21x^3
15z^6y^3 - 30z^9 + 2z^6y^2
64n^2 + 2n^3
4x^2 + 2x^2
18x^5y + 45x^7y
x^3 + 3x^2
