Question

1) what is the initial value?

Answer 1

Step-by-step explanation:

1) for t = 0, the initial value is -0.45 gal. which is funny. when it is really cold, do people add water to the tank somehow instead of consuming water ?

so I guess, that system is really reliable with values greater than 0.

0.0875t = 0.45

t = 5.142857143...°

so, I guess, 6° is the lowest reasonable value for this function.

2) as for any line function, the slope is the rate of change.

so, 0.0875 gal more per 1 degree more in temperature.

3) t = 90

w = 0.0875×90 - 0.45 = 7.425 gal