graph those points given, in a cartesian plane grid,
that is, an x,y axis grid
and try to make a straight line from the leftmost, to
the rightmost, they don't really line up as a straight
line, so... try to draw a line that will cover "most of
the points", there will be a couple or so "outliers",
the line that "covers most of the points" is so-called
"best-fit" line, so, using that line, try to get what
"y" is, when x = 3