FINAL GEOMETRY QUESTION!! PLEASE HELP

Step-by-step explanation:

The error was in Step 2.  The student attempted to "complete the square" by adding 4 to x^2 + 4x and then subtracting 4 from the other side of the equation.  

The work, if done correctly, would look like this:

x^2 + 4x + 4 - 4 = -y^2 + 20.

This condenses to:

(x + 2)^2 - 4 + y^2 = 20

(x + 2)^2 + y^2 = 24

This circle has its center at (-2, 0) and its radius is √24 = √4√6, or 2√6

good job you smart son of a gun you are smarter that einstein. 7