Answers

  • Brainly User
2015-11-24T01:29:42+08:00
Standard Equation of circle whose center is not at origin (0, 0):
(x - h)² + (y-k)² = r²

where (h,k) = center of the circle
r = radius  (If diameter is given, divide it by two to get the radius.)

Radius: 18/2 = 9 units
Center: (h, k) = (-3, 8)     h= -3       k= 8

Solution:
(x - -3)² + (y - 8)² = 9²
(x+3)² + (y-8)²  =  81   Standard Form

General Form:  x² + y² + Cx + Dy + E = 0
(x+3)² + (y-8)² = 81
x² + 6x + 9 + y² - 16y + 64 = 81
x² + y² + 6x -16y + 9 + 64 = 81
x² + y² + 6x - 16y + 73 - 81 = 0
x² + y² + 6x - 16y - 8 = 0

Standard Form:   (x + 3)² + (y - 8)² = 81

General Form:  x² + y² + 6x - 16y -8= 0


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