How can i solve this problem step by step 9÷3.33

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

Assume that y varies inversely with x. if y=1.6 when x=0.5 find x when y=3.2

What is the ratio fraction form of 25: 9