Please help! serious answers only

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

Jenisey has $24 to spend on seven pencils. after buying them she had $10. how much did each pencil cost.?

If you could answer these your a life saver