Alake near the arctic circle is covered by a thick sheet of ice during the cold winter months. when spring arrives, the warm air gradually melts the ice, causing its thickness to decrease at a rate of 0.2 meters. after 7 weeks, the sheet is only , 2.4 meters thick.
let y represent the ice sheet's thickness (in meters) after x weeks.

complete the equation for the relationship between the thickness and number of weeks.