Answer: 1. C(12) 2. B(n-1-14) 3. A(30)
Step-by-step explanation: For number one the nth term with common difference d and first term a is a+(n-1)d=nth term, plug in the values you have and solve for n to get 12. For number 2 an algebraic expression has a variable and a constant but doesn't have an equal sign. So it is B. For number three just add them up. Hope this helped!