A lake near the Arctic Circle is covered by a 2-meter-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 constant rate. After 3 weeks, the sheet is only 1.25 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.

y=

The table below shows the approximate masses of a dust particle and a grain of pollen. dust particle 0.000000778 g grain of pollen 0.00000000155 g the mass of a dust particle can be estimated and written in the form a × 10^b, where a = 8 and b = the mass of a grain of pollen can be estimated and written in the form a × 10^b, where a = 2 and b = based on the estimates, the mass of a dust particle is approximately blank times larger than the mass of a grain of pollen.