# Math Help - find the center of the circle and radius from this equation.

1. ## find the center of the circle and radius from this equation.

x
2 + y2 2x +10y +9 = 0

2. Originally Posted by philjerry
x
2 + y2 2x +10y +9 = 0
You have $(x^2 - 2x) + (y^2 + 10y) + 9 = 0$. Complete the square for the x and y quadratics and simplify. If you need more help, please show all your work and say where you get stuck.

3. Complete the square on the $\displaystyle x$ terms, complete the square on the $\displaystyle y$ terms, and move any remaining constants to the RHS.

This will put the equation into the required form, i.e. $\displaystyle (x - h)^2 + (y - k)^2 = r^2$.