(Psst, this should have been posted in the Pre-Algebra/Algebra subforum.)
Oops! That's not how to do it. You have to square both sides this way:
On the left side, both the 3 and x get squared. On the right side, the square-root and the power of 2 "cancel-out":
Then use the quadratic formula to solve for x.
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EDIT: Beaten to it...
Even though others have pointed out an earlier mistake you made, I just want to let you know that there's a problem with this step, also. When taking the square root of both sides of an equation, you need to use the plus-or-minus sign, unless the question specifically tells you the answer is positive. Hence
.
Of course, as I and others have said, this is still not the correct value of for your problem; I just wanted to point out another place you went wrong in the hope of being helpful.
Also, ignoring the fact that you arrived at step 2 incorrectly, when going from step 2 to step 3, you need to FOIL.
For the love of (insert deity here), please remember this next time. I can't tell you how many times I've seen people make the same mistake. It's a pet peeve of mine. Arrrrgh!
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