Neither of them are fully correct because the equation of a circle is:
[tex](x - h) ^{2} + (y - k) ^{2} = r ^{2} [/tex]
h = x value of center coordinate
k = y value of center coordinate
r = radius
Therefore, the correct equation of the circle is:
[tex](x + 3) ^{2} + (y - 1) ^{2} = 49[/tex]
David had the correct values in each of the parentheses while John had the correct value on the right side of the equation.