Question

A circle is described by the equation x2 + y2 + 14x + 2y + 14 = 0. What are the coordinates for the center of the circle and the length of the radius?

a. (-7, -1), 36 units
b. (7, 1), 36 units
c. (7, 1), 6 units
d. (-7, -1), 6 units

Answer 1

`x^(2)+y^(2)+14x+2y+14=0 \\ \\ x^(2)+14x+49 +y^(2)+2y+1-36=0 \\ \\ (x+7)^(2)+(y+1)^(2)=36 \\ \\ S=(-7,-1) \\ \\ r=6`

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`(x-a)^(2)+(y-b)^(2)=r^(2) \\ \\ S=(a,b)`