(x-(-1))^2+(y-(7))^2= 8
to find the center or the values that are placed in the parentheses you find the midpoint of the diameters using the midpoint formula.
[tex]( \frac{ x_{1} + x_{2} }{2}, \frac{ y_{1} + y_{2} }{2})[/tex]
plug in the points
[tex]( \frac{ -3 + 1 }{2}, \frac{ 5 + 9 }{2}) = (-1,7)
[/tex]
(-1,7) is the center to plus in to parentheses.
to solve for radis squared plug in one of the endpoints for x and y in the circle equation and the center in the points as well.
circle formula is
[tex](x-h)^2 +(y-k)^2 = r^2[/tex]
plug in and solve for radius squared
[tex](1-(-1))^2 +(9-(7))^2 = r^2[/tex]
[tex](-2)^2 +(2)^2 = 8 = r^2 [/tex]
plug in 8 for the radus squared at the end.
