Answer:
- center: (-9, -7)
- radius: 5
Explanation:
A graphing calculator can be helpful for questions of this nature. The attached shows the center is (-9, -7) and the radius is 5.
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You can separate the x- and y- terms and complete the square for each.
(x^2 +18x) +(y^2 +14y) = -105
Do that by adding the square of half the linear term.
(x^2 +18x +9^2) +(y^2 +14x +7^2) = -105 +81 +49
(x +9)^2 +(y +7)^2 = 25
Compared to the standard form equation ...
(x -h)^2 +(y -k)^2 = r^2 . . . . . . . center (h, k), radius r
We see that the given circle has a center of (-9, -7) and a radius of 5.