Question

Which point lies on a circle with a radius of five units and center at P(6,1)

Answer 1

Add tye radius with the X coordinate
(6+5,1 ) = (9,1)

Then subtract it from X
Or add & subtract the radius with the Y axis

And you will get the answer

Answer 2

The equation of a circle is:

(x-h)^2+(y-k)^2=r^2

Where (h,k) is the center of the circle and r is the radius of the circle. In this case we have (6,1) for the center and a radius of 5 so:

(x-6)^2+(y-1)^2=25

So any point that satisfies that equation lies on the circle.