I have designed solid slab with free end in two sides. It's dimension was (3 x 4 m). If you have any suggestions about this subject; please inform us.

use3/8"dia bar @8" c/c both end, top extra bar3/8"dia8" c/c, for shear L/3 lenght.

If it was properly calculated, and slab thickness and rebars was used according calculation, then all OK.

You provided not enough information for any accuracy advices.