A. Find the sum of the following,

1. 6a + 7a

2. -9no + 24no

3. -21(x + y) + 6(x + y) + [ -4(x + y)] + [-9(x + y)] +10 (x + y)

4. (7a + 9b) + (5a + 6b)

5. (20x + 10y) + (-22y)
​