Ageism in Tenure-track applications
The aspect of ageism and whether it plays a positive or negative role differs from one institution to another. 


  I  worked many years in industry before PhD


The effect this would have on your application largely depends on what type of work are you associated with in the industry -- how well it attributes your tenure track position. 


  Should I hide my B.Sc. degree date?


Frankly, I don't think this is a good idea. It is not professional and is not recommended for a CV. In fact, it might have the opposite effect of drawing attention to the information you wish to conceal.