Write an algebraic expression to represent the length of each segment shown below.

1. 

   Answer (a):

   $n + n + n + 15$ or $3n + 15$

2. 

   Answer (b):

   $17 + x + x + 10$
   Can you find a simpler way to write this expression?

3. 

   Hint (c):

   See parts (a) and (b).