
Answer:
x - y = Â - Â 0.25 cups.
Step-by-step explanation:
Let x : Â The number of cups of water Ashley is supposed to use
  y :  The  number of cups of water she actually uses
The actual measurement of water for 1 glass lemonade = 3/ 4 cup
So, the measurement of water for 5 glass lemonade Â
= Â 5 x ( Measure of water for 1 glass) = [tex]5 \times (\frac{3}{4})[/tex]
The amount of water Ashley actually uses for 5 glass lemonade  = 4 cups
⇒  [tex]x = 5 \times (\frac{3}{4})[/tex]  = 3. 75 cups
  and  y = 4 cups
So, x - y = 3.75 cups  - 4 cups = -0.25 cups.
Hence, she used the amount 0.25 cups water extra while making 5 glass lemonades according to the given recipe.