Help!! Im stuck on this!

(2x + 3) + (3x + 5)
(8x^2 - 3x +3) + (2x^2 -4x +6)

3 * (2x - 6)
2x * (5x + 11)

*****

(2x + 8) - (4y + 1)
-5x * (3x^2 - 2x - 1)

What do we need to watch for in problems like this?