Question

4. Find the center and radius of the circle with equation x2 + y2-2x + 4y - 11 = 0

Answer 1

Answer:

x^2+y^ 2+2x-4y-11=0

x^2 + 2x + ? +y^2 - 4y + $ = 11 + ? + $

x^2 + 2x + 1 + y^2 - 4y + 4 = 11 + 1 + 4

(x + 1)^2 + (y - 2)^2 = 16

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

Center (-1,2) and radius = 4 (see bold in line above)

Step-by-step explanation:

Answer 2

Answer:

(1 , -2) and r = 4

Step-by-step explanation:

x² + y² - 2x + 4y - 11 = 0

x² - 2x + 1 - 1 + y² + 4y + 4 - 4 - 11 = 0

(x - 1)² - 1 + (y + 2)² - 4 - 11 = 0

(x - 1)² + (y + 2)² = 16

We know equation of circle is of the form

(x - h)² + (y - k)² = r²

So, center is (1 , -2) and radius is 4