How are the values of the eights in 880 relared

The vertices of a triangle are a(7,5), b(4,2), c(9,2). what is m

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

Given that ot =5, xt=12, and ox= 13 is xy tangent to circle o at t? explain.