Trudy bought a $20 prepaid long distance phone card. for every minute that she talks, $0.25 is deducted from her card. The funct
ion f(m)=20-0.25m represents the amount of money f(m) she has left after talking m minutes.FInd the zero and explain what it means in the context of the situation.
Given the function f(m)=20-0.25m to represent the amount of money f(m) she has left after talking m minutes, the zero of the equation can be gotten by setting f(m) to 0
f(m)=20-0.25m
0 =20-0.25m
-20 = -0.25m
m = -20/-0.25
m = 80
Hence Trudy will have talked for 80minutes if she has no money left
