Write the equation in standard form of the circle whose center is (3,-5) and passes through point (7,1)

We can use the distance formula ro find the radius

r = √  ( [ 7 - 3]^2  +  [ -5 -1 ]^2 )   =  √ [ 4^2 + (-6)^2  ]  = √ [16 + 36]  = √52

So......the equation  is

(x - 3)^2  + ( y + 5)^2  = 52