Answer:
3. 2
4. f(n) = 3 + 4(n - 1)
Step-by-step explanation:
3. The general term of the arithmetic sequence is given by:
                                     A(n) = - 14 + (n - 1)(2)
To find the ninth term of this arithmetic sequence, just put  in the general term.
 in the general term.
∴ A(9) = - 14 + (9 - 1)(2) = - 14 + 8(2) = -14 + 16 = 2.
Therefore the ninth term in the arithmetic sequence is two.
4. To know which expression represents the given sequence, substitute different values for  to conclude.
 to conclude.
In Option A, f(n) = 4 + 3(n - 1). Substitute n = 1.
We get f(1) = 4 + 3(0) = 4. This is not the first term in the sequence and can be eliminated.
In Option B, f(n) = 4 + 3n. Substitute n = 1.
We get f(1) = 4 + 3(1) = 7, not 3 so can be eliminated.
Similarly in Option C, we get 7 and could be eliminated. 
In Option D, f(n) = 3 + 4(n - 1). Substitute n = 1.
We get f(1) = 3 + 4(1 - 1) = 3, which is the first term in the sequence.
Similarly, f(2) = 3 + 4(2 - 1) = 3 + 4 = 7.
Substitute n = 3, 4 to get other terms as well.
So, we say f(n) = 3 + 4(n - 1) is the representation of the given arithmetic sequence.