posted by K
A bathtub is draining at a constant rate. After 2 minutes, it holds 28 gallons of water. Three minutes later, it holds 7 gallons of water. Write an equation that represents the number y of gallons of water in the tub after x minutes.
we have two data points: (2,28) and (5,7)
so, the slope of the line is (7-28)/(5-2) = -7
Using the point-slope form of a line, the function is
y-28 = -7(x-2)
y = 42-7x