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

Hello : 
x² + y² + 14x + 2y + 14 = 0
(x²  + 14x) + (y²+ 2y) + 14 = 0
(x²  + 14x+49-49) + (y²+ 2y+1-1) + 14 = 0
(x²  + 14x+49)-49 + (y²+ 2y+1)-1 + 14 = 0
(x+7)² + (y+1)² =6²...(answer : D(-7, -1), 6 units )