#### Answer

The completed table is:

#### Work Step by Step

The algebraic expression that is to be used for completing the table is
$$\dfrac{100x+5000}{x}$$
In this case, $x$ is equal to $10$, $100$ and $1000$
Substitute each value of $x$ into the expression and evaluate to complete the table:
$x=10$
Cost per Bookshelf $=\dfrac{100(10)+5000}{10}=600$ dollars
$x=100$
Cost per Bookshelf $=\dfrac{100(100)+5000}{100}=150$ dollars
$x=1000$
Cost per Bookshelf $=\dfrac{100(1000)+5000}{1000}=105$ dollars
The table is shown below: