Question

Find the center and radius of the circle
x2 + 2x - 1 + y2+ 4y = 3

Answer 1

Answer:R=3\\

(a,b)=(1,2)

Explanation:

`(x-a)^(2)+(y-b)^(2)=R^(2)\\(a,b)-center\\R-radius\\x^(2) + 2x - 1 + y^(2)+ 4y = 3\\(x+1)^2=x^(2)+2x+1\\(y+2)^(2)=y^(2)+ 4y+4\\x^(2) + 2x - 1 + y^(2)+ 4y = (x+1)^2-1+(y+2)^2-4-1=(x+1)^2+(y+2)^2-6=3\\(x+1)^2+(y+2)^2=9\\R=3\\(a,b)=(1,2)`