The equation is .

                                   (Subtract 4 from each side) \ \

(Square each side and eliminate the square roots)

\ \

Apply formula: .

\ \

         (Subtract from each side) \ \

( divide into factors )

\ \

\ \

                                             (Simplify) \ \

Check:

To check the solution, substitute in .

                                                            (Evaluate square roots: )

The solution is "True".

Check:

To check the solution, substitute in .

                                                             (Evaluate square roots: )

The solution is 6.