Consider that the domain are the set of x values with a point on the curve.
In this case, based on the grap, you can notice that the domain is:
domain = (-8,2)
domain = {-8,-7,-6,-5,-4,-3,-2,-1,0,1,2}
In this case you can observe that the circle has a left limit given by x = -8 (this can be notices by the subdivisions of the coordinate system) and a right limit given by x = 2. That's the reason why it is the interval of the domain.
The range are the set of y values with a point on the curve.
range = (-3,7)
range = {-3,-2,-1,0,1,2,3,4,5,6,7}
In this case, you observe the down and up limits of the circle.