Simplify each expression in parts (a) through (c) below. Then complete part (d).

1. $xy(\frac{1}{x}+\frac{1}{2y})$ 

   Hint (a):

   Distribute the $xy$ to both terms in the parentheses ( ).
   Then simplify.

   Answer (a):

   $\textit{y}+\frac{\textit{x}}{2}$

2. $ab(\frac{2}{a}+\frac{4a}{b})$ 

   Answer (b):

   $2b+4a^2$

3. $2x\left(3−\frac{1}{2x}\right)$ 

4. What expression would go in the box to make the equation $\square(\frac{2}{x}+\frac{7}{y})=2y+7x$ true?

   Hint (c) and (d):

   See the previous parts of this problem for clues.