What is the center and radius of the circle with equation x2 + y2 + 6x + 16y + 64 = 0?

Hello,
 
By making factors:

The major difference is that a histogram is only used to plot the frequency of score occurrences in a continuous data set that has been divided into classes, called bins.  bar charts, on the other hand, can be used for a great deal of other types ofvariables  including  ordinal  andnominal  data sets.

Understanding what? lol