Answer:
a)
(i) 43, 56
(ii) -1,3
b)-27
c) -21 +4n
Explanation:
For a,i, you can see that it decreses by 7 each time so you subtract 7 from 50 to get 43, then you subtract 7 from that to get 56. For a,ii it increases by 4 each time so you add 4 to -5 to get -1, then add 4 to that to get 3. For b, because it is the 15th term you are looking for, you can plug 15 into the equation as n so 78-7n to 78- 7*15, 78-105, -27. For c, you know that each time it increases by 4, so you know you add 4n, and then for the base, you have to find the term before -17 so you subtract 4 to get -21. Put it together and get -21+4n.