Question

Which conic section does the equation below describe? x^2+y^2+2x-8y-13=0

Answer 1

Answer:  B) Circle

Step-by-step explanation:

First, complete the square:

x² + 2x +  1    + y² - 8y +  16   = 13 +  1   +  16  

       ↓       ↑             ↓         ↑

   (2/2) = (1)²          (-8/2) = (-4)²

       (x + 1)²    +             (y - 4)²   =  30

The result is a circle whose center is (-1, 4) and radius is √30