How to make a cell within excel display nothing (show blank) if a related cell is empty?

I have the following formula inside cell BC39: IF(BA39>0,"HIGHER",IF(BA39<0,"LOWER","FLAT")).  
The formula works fine, except that if the value of cell BA39 has not been entered yet, cell BC39 always displays FLAT.  If the value of cell BA39 has not yet been entered, I want cell BC39 not to display anything and show empty until I have entered the value into cell BA39.
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Sam Simon NasserIT Support ProfessionalCommented:
what will happen if you put like this?

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Rory ArchibaldCommented:
You can use:

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Microsoft Excel

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