What is the right answer for 9i x 2i?

How long must $542 be invested at a rate of 7% to earn $303.52 in interest? in a easier way

The customer price index(cpi), which measures the cost of a typical package of customer goods,was 208.8 in 2011 and 244.1 in 2016.let x=11 corresponding to the year 2011 an estimate to cpi into 2013 and 2014. assume that the data can be modeled by a straight line and the trend to continue idenfinitely.use data points to find such a line and then estimate the requested quantities

Find the percent error of the measurement 4 cm