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

The equation of a circle:
( x - p )² + ( y - q )² = r² ( where p and q are coordinates for the center )
x² + y² + 14 x + 2 y + 14 = 0
( x² + 14 x + 49 ) + ( y² + 2 x + 1 ) - 49 - 1 + 14 = 0
( x + 7 )² + ( y + 1 )² = 50 - 14
( x + 7 )² + ( y - 1 )² = 36
p = - 7, q = - 1, r = 6
Answer: D ) ( - 7 , - 1 ), 6 units