In the same way that we were able to write down the equation of a straight line in Section 12.2, we can also write down the equation of a curved line. The techniques of plotting these curves are very similar to plotting a straight line, but there are some precautions that need to be taken. If we want to know what the curve y = x2 − 2x − 6 looks like for values of x between −3 and −5, then it is necessary to draw up a table of values. In order to avoid mistakes, the table is expanded in the following way:
