The quotient of 45 and 4 2/5? What is the expression for that ?

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

Ineed me i stuck and i don’t want to get it wrong

2. explain in words how you plot the point (4, −2) in a rectangular coordinate system.