14. rewrite the following definition as a biconditional:

points that lie on the same line are collinear.

if a point lies on a line, then it is collinear.
if a point lies on a line with another point, then the two points are collinear.
if two points are collinear, then they lie on the same line.
points lie on the same line if and only if the points are collinear.

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