Then that is a totally incompetent program or you do not know how to use it. I suspect that you are not using enough grouping symbols.
Look at my LaTeX code:
7\sqrt{1-7\sqrt{1-x}} this gives .
Note how carefully the various parts are grouped together using grouping symbols.
Does that program allow LaTeX coding?
If so the you can copy and paste from here.
In any case, you need to contact the program administrator to discuss these concerns.