While your motherboard may support hybrid crossfire, it won't work with a 7750! The graphics chip on a 760G motherboard is based on the Radeon 3450 - an ancient and very low powered design. The highest card you could ever use in hybrid crossfire with it was the 4350,
iirc.
tbh, Even if you could run them both together, performance would be worse than the 7750 on its own due to the overhead of managing crossfire. Did I mention that the 760G graphics are
really slow?
Just sit back, run your 7750 on its own, and enjoy