F(x)=125-(125*0.2x)
to find the value of the phone after 3 years, you put x=3.
f(3)=125-(125*0.2(3))
f(3)=50
Answer: 486 glasses of water in 9 weeks
Step-by-step explanation:
54 X 9 = 486
Or you could add 54 to itself 9 times then you will get 486
Answer is option 4. working out attached
hope it helps :)