Question

Find the centre and radius of the circle x2 + y2 + 2x - 4y -4=0
(1) (1, 2), 3
(2) (-1, -2), --3
3) (-1,2), 3
(4) (1, -2), 3​

Answer 1

Answer:

1

Step-by-step explanation:

answer is correct plz point

Answer 2

Answer:

3) (-1,2), 3

Step-by-step explanation:

Comparing the equation with x2 + y2 + 2gx + 2fy + c = 0

We get g = 1, f = -2, c = -4

Center of circle is (-g, -f) = (-1, 2)

Radius formula is

$\sqrt{g^{2}+f^{2}-c }$ = $\sqrt{1+4-(-4) }$ = $\sqrt{9}$ = 3