David thinks of a positive number. He squares it and multiplies the result by 6. He then adds on his original number and gets an answer of 15. What number is David thinking of. Give your answer as a fraction in its simplest form.

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