5 man premades

They aren't going to be doing any decent team coordination a solo player doesn't do in Bronze 3. If they could coordinate well they wouldn't be in B3, so simply being better than them as an individual and working with your team is how you beat them. Review your deaths and losses and try to learn from them, and take the time to read up on pro guides and watch high elo streams, and never think you cannot improve.

Ward.