Subtract from both sides of the equation.

Use the form , to find the values of , , and .

Consider the vertex form of a parabola.

Substitute the values of and into the formula .

Cancel the common factor of and .

Factor out of .

Cancel the common factors.

Factor out of .

Cancel the common factor.

Rewrite the expression.

Divide by .

Find the value of using the formula .

Simplify each term.

Cancel the common factor of and .

Factor out of .

Cancel the common factors.

Cancel the common factor.

Rewrite the expression.

Divide by .

Multiply by .

Subtract from .

Substitute the values of , , and into the vertex form .

Substitute for in the equation .

Move to the right side of the equation by adding to both sides.

Use the form , to find the values of , , and .

Consider the vertex form of a parabola.

Substitute the values of and into the formula .

Cancel the common factor of and .

Factor out of .

Cancel the common factors.

Factor out of .

Cancel the common factor.

Rewrite the expression.

Divide by .

Find the value of using the formula .

Simplify each term.

Raise to the power of .

Multiply by .

Divide by .

Multiply by .

Subtract from .

Substitute the values of , , and into the vertex form .

Substitute for in the equation .

Move to the right side of the equation by adding to both sides.

Add and .

Add and .

This is the form of a circle. Use this form to determine the center and radius of the circle.

Match the values in this circle to those of the standard form. The variable represents the radius of the circle, represents the x-offset from the origin, and represents the y-offset from origin.

The center of the circle is found at .

Center:

These values represent the important values for graphing and analyzing a circle.

Center:

Radius:

Find the Center and Radius x^2+y^2+4x+8y+16=0