Question

Find the equation of the circle with center at (-3,1) and through the point (2,13)

Answer 1

Try this option:
1. if centre of the circle is O(-3;1) and P(2;13), then OP=√(5²+12²)=13=r (radius);
2. in common view an equation of the circle is: (x-a)²+(y-b)²=r², where (a;b) is the centre.
Using this: (x+3)²+(y-1)²=13²