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a circle is described by the equation x squared + y squared + 14 x + 2 y + 14= 0 what are the coordinates for the center of the circle and length of the radius

User Dontcare
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The standard equation of any circle is:
(x-h)^2 + (y-k)^2 = r^2 where:
r is the radius and (h,k) are the coordinates of the center of the circle.

Now, the given equation is:
x^2 + y^2 + 14x + 2y + 14 = 0

We will try to use the given equation to reach the standard form of the equation of circle as follows:
(x^2 + 14x) + (y^2 + 2y) + 14 = 0
(x^2+2(7)(x) +7^2) - 7^2 + ( y^2+(2)(1)y+1^2) -1^2 + 14 = 0
(x+7)^2 +(y+1)^2 = 36 = (6)^2

Comparing the equation we reached to the standard form, we will find that:
-h = 7 .............> h=-7
-k = 1 ..............> k=-1
r^2 = 36 .............> r = 6

Therefore:
The center is found at: (-7 , -1)
radius = 6
User Sany
by
8.6k points
2 votes
(x-h)^2+(x-k)^2=r^2
x^2+14x+___+y^2+2y+__= -14 (14/2)^2 = 49, (2/2)^2=1
x^2+14x+49+y^2+2y+1= -14+49+1
(x+7)^2 + (x+1)^2 = 36
Center= (-7, -1) Radius= square root of 36 so 6
User Vivek Raskar
by
8.4k points

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