The equation is .

                        (Subtract 4 from each side)

(Square each side and eliminate the square roots)

                           (Simplify)

(Subtract from each side)

( divide into factors )

                   (Apply zero product property) \ \

                                (Simplify) 

Check:

To check the solution substitute in .

\ \

                                                (Evaluate square roots: )

The solution is "True".

The solution is "True".