Question

Identify the center and the radius of each circle.

C. X^2+2x+1+y^2+4y+4=9

Answer 1

`Center =(-1,\: -2),\: radius = 3\: units`

Explanation:

• 
  `x^2 +2x + +1 + y^2++4y+4=9` (Given equation of circle)

• 
  `\implies (x^2 +2x + +1) + (y^2++4y+4)=(3)^2`

• 
  `\implies (x+1)^2 + (y+2)^2=(3)^2`

• Comparing the above equation with standard form of circle i.e.
  `(x-h)^2+(y-k)^2=r^2`, we find:

• 
  `h=-1, \: k = -2,\: r = 3`

• 
  `Center =(h, \: k )=(-1,\: -2),\: radius = 3`