Answer: -14 gallons.
Explanation:
Given : Seven days ago, the gas tank on Roses car was filled with 20 gallons of gasoline.
Today there are 6 gallons of gasoline.
∵ 20> 6 , it means there is decrease in the amount gasoline.
Change of gasoline in the past seven days = Amount gasoline seven days before- Amount gasoline now .
i.e. Change of gasoline in the past seven days = 20 gallon - 6 gallons=14 gallons
Since decrease is represented by negative (-) sign in integers.
∴ The integer represents the change of gasoline in the past seven days = -14 gallons.