Answer:
1. 2x + 8y = 10xy
2. 13ab + 15ab = 28ab
Explanation:
This is because for question 2 the "a" and "b" stay together since it's on 13 and 15. So that is why you would get 28ab. For question 1 it's basicly the same but instead, you combine the two to get your answer.
Hope this helps.