Answer:
The equation of circle is  +
+ = 18
 = 18
Step-by-step explanation:
Given the endpoints of the diameter of a circle: (-2,-3) and (4,-1)
We know that the equation of circle is
 +
 +  =
= 
where (x,y) is any point on the circle, (h,k) is center of the circle and r is radius of circle.
To find (h,k): the center is midpoint of diameter
Midpoint of diameter with end points (x1,y1) and (x2,y2) is given by
(   ,
 ,  )
  )
(  ,
 ,  )
  )
(1,2)
Hence (h,k) is (1,2)
Substituting values of (h.k) and (x.y) as (1,2) and (4,-1) respectively in equation of circle, we get 
 +
 + =
 = 
 = 18
 = 18
Now substituting values of (h,k) and  in equation of circle, we get
 in equation of circle, we get
 +
+ = 18
 = 18
Hence the equation of circle is  +
+ = 18
 = 18