The rate of change is also called the slope
the formula foe the rate of change is (y2-y1) / (x2-x1)
x1 = -3
x2 = 6
y1 = 14
y2 = -1
rate of change = (-1 - 14) / (6- (-3)
= -15 / 9
= -5/3
You would multiply the tanks by gallons
36x205
= 7,380
I think it’s 5. I’m not sure