Write the standard equation for the circle with center at (4,-1) and passing through the point (0,1)

hello :
an equation of the circle Center at the A(a,b) and ridus : r is :
(x-a)² +(y-b)² = r²
in this exercice : a =4  and b = -1 (Center at the origin)
r = AP P(0.1)
r² = (AP)²
r² = (4-0)² +(-1-1)² = 16+4=20
an equation of the circle that satisfies the stated conditions.
Center at A(4,-1), passing through P(0, 1) is :  (x-4)² +(y+1)² = 20

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