Question 1030521: what is the center and radius of the circle expressed by: x^2+y^2+10x-2y-10=0
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! x^2+y^2+10x-2y-10=0;
x^2+10x+y^2-2y=10
complete the square on the left, and add the constants to the right.
x^2+10x+25+y^2-2y+1=36. Now write as squares.
(x+5)^2+(y-1)^2=6^2. Change the sign of the constant on the left, and that gives the (x,y) for the center.
This is a circle with center (-5,1) and radius 6. The radius is the square root of the number on the right.
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