Running-gag assumed you meant this:
Is that correct, or is it:
? Can't really tell.
If running-gag is correct, then the simplification would go this way:
Square both sides:
Bring everything to the left side except for the radical term:
Divide by -2:
Square both sides again to eliminate the radical:
Move all terms to the left, combine terms, and set the left side equal zero.
Do these solutions check out if you substitute them in the original radical equation? Are they within the domain that Running-gag set up for you at the beginning?