What is two thirds minus one fifth?

7/15

Step-by-step explanation:

First, we have to make the bottom part the same:

2/3 - 1/5 = 10/15 - 3/15

10 - 3 = 7 = 7/15

f(x) has value 150 at x= 0

and 0 at x= 3

so d(f(x))/dt = slope = -150/3 = -50