Let the previous price of the gas be represented by = x
Let the current price of the gas be represented by = y
As given, during the past 7 days they have lowered the price of regular gas by $0.2 each day.
This means after 7 days the price has been lowered by = $1.4
[tex]0.2\times7=1.4[/tex]
Equation becomes:
[tex]y=x-1.4[/tex]
So, total change in the price in 7 days is $1.4 less than the previous amount.