Answer:
The center is located at (-1, -2), and the radius is 5.
Step-by-step explanation:
The general equation of a circle is given as
(x - a)^2 + (y - b)^2 = r^2
where
a and b are the centre of the circle and r is the radius
Given the equation
x2 + 2x + y2 + 4y = 20
add 1 ad 4 to both sides
x2 + 2x + 1 + y2 + 4y + 4 = 20 + 4 + 1
factorise
(x +1)^2 + (y+2)^2 = 5^2
comparing with the general equation
a = -1, b = -2, r = 5 (all measured in units)
