Consider the diagram of three pieces of lumber shown below.

$\underline{{4}\text{ meters}} \quad \underline{\ \ \ {x}\ \ \ } \quad \underline{\ \ \ {x}\ \ \ }$ 

1. If $x = 6$ meters, how long are all three pieces of lumber laid end to end?

   Hint (a):

   Since $x = 6$ meters, the three pieces of lumber now look like this:

   $\underline{{4}\text{ meters}} \quad \underline{{6}\text{ meters}} \quad \underline{{6}\text{ meters}}$

   Can you find the total length of the lumber pieces?

2. If the total length of all three pieces laid end to end is $20$ meters, what is the value of $x$?

   Hint 1(b):

   
   Using the diagram above, can you write an expression to represent the pieces of lumber?

   Hint 2(b):

   If $4 + x + x = 20,$ why must $x + x = 16$?

   More Help (b):

   Can you find the value of $x$?