Using data from 2002 projected through 2016, the number of worldwide users of the Internet, in billions,

Question:

Using data from 2002 projected through 2016, the number of worldwide users of the Internet, in billions, can be approximated quite accurately either by
(1) y = 0.207t - 0.000370 or by
(2) y = 0.00454t2 + 0.126t + 0.271
with t equal to the number of years past 2000 (Source: dailytech.com).
(a) Which of the equations is more accurate for 2013, when the number was 2.70 billion?
(b) Use both formulas to estimate the number of users in 2018?