PLeeeaaasee help as fast as physically possible

The general form of the quetion of a circle is ax^2+by^2+cx+dy+e=0 where a=b=0 if the circle has a radius of three units and the center lies on the y axis which set of values of a, b, c, d, and e might correspond to the circle

The number of branches on a tree demonstrates the fibonacci sequence. how many branches would there be on the next two levels of this tree? 13 | | | m branches

What numbers are included in the set of integers? what numbers are not included?