Question

find the centre and radius of circle x2 + y2-2x+4y-4=0​

Answer 1

Answer:

x²+y²-2x+4y-4=0

on adding both sides with 5

x²-2x+1+y²+4y+4=9

(x-1)²+(y+2)²=9

radius=3

centre=(1,-2)