Show that the equation represents a circle by rewriting it in standard form, and find the center and radius of the circle.

5x^2 + 5y^2 + 10x - y = 0

5x^2 + 5y^2 + 10x - y = 0 it is the same of

x^2 + y^2 + 2x - 1/5y = 0

and then

(x + 1) ^2 - 1 + (y-1/10) ^2 - 1/100=0

(x + 1) ^2 + (y - 1/10) ^2 = (101/100)

the center is C (-1, 1/10), and the radius is R = sqrt (101) / 10