1 gallon = 4 quarts
1 Quart = 2 pints
1 Pint = 2 cups
2 (amount of pints in a quart) x 5 (amount of quarts) = 10 = how many pints
10 x 2 (amount of cups in a pint) = 20
20 = how many cups in 5 quarts
As your question is stated, there is no answer!
I'm going to assume the polynomial you meant is:

To create a perfect square trinomial, take half the coefficient of x and then square it.

In all problems like this, you want to square half the coefficient of x -- always half.
The number 7 should be removed from his list to make the list accurate.