H e l p w o u l d b e g r e a t ; - ;

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

Which geometric principle is used to justify the construction below?

Find the degree 3 taylor polynomial p3(x) of function f(x)=(-3x+15)^(3/2) at a=2