If your only option is to select the word, I would select agreed for both of the first two sentences. However, there are other mistakes as well. Here is what I would say:
I agree with my mother (or, I am in agreement with my mother)
I agree with the idea of selling books at high prices
Agree with (or be agreeable to)
I am worried about the current situation in my country.
Be worried about . . .
I am worried about the current economic situation in my country
I waved to him at recess to get his attention
Student or Learner