Answer:
A circle has a special form:
if it has a center (cx,cy) and a radius r all its (infinite many) points (x,y) will satisfy the equation (x−cx)2+(y−cy)2=r2
An equation describes the relationship between two expressions or functions, if it has only one solution than this will be shown as point in a graph which shows both input and output of said functions.
An equation always has a graph (unless the expression or function is undefinied) even if it has no solution. For example 5x+9=5x−9 is wrong for all values of x however we can plot both of these parallel lines:
