My question is in the description, it wont fit in the title q-q

Question

A bathtub containing 42 gallons of water is draining at a constant rate. After 2 minutes, it holds 30 gallons of water.  Write an equation that represents the number y of gallons of water in the tub after x minutes.

Answer 1

Let g(x) be the number of gallons left in the tub after x minutes. If the tub loses 12 gallons in two minutes (42-30=12), then it's losing 6 gallons per minute (x). So, the equation is:

g(x) = 42 - 6x

Note that the number of gallons will be 0 when x = 7, so the domain of the function is 0 ≤ x ≤ 7.