A bathtub is draining at a constant rate. after 1 minute, it holds 32 gallons of water. Four minutes later, it holds 16 gallons of water. Write an equation that represents the number y of gallons of water in the tub after x minutes.

Y=-4x.

The bath is draining at a constant of 4 gallons per minute. The constant is also the slope. Because the number of gallons in the tub is decreasing and the number of minutes is increasing the slope will be negative giving you the expression y=-4x