You can put this solution on YOUR website!
Well, your initial idea is right on!
Where A = original area and x = the original length of the side of the square.
The next step is to recall that
, that is; the original area (A) is equal to the original sides squared
, so substitute the A with
in the first equation then solve for x.
Expand the left side.
from both sides.
Subtract 9 from both sides.
Finally, divide both sides by -6.