Can I have a help from someone

What is the point-slope form of the equation for the line with a slope of -2 that passes through (1,4)?

Answer question above and explain each step : )

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