Two rear tires replaced on a front wheel drive car, now pulls?

Balance has nothing to do with pulling. Your back tires should have lasted longer than the fronts because the front tires are driven by the Motor and . Go get a 4 wheel alignment. I'd put the new tires on the front. Make sure the hand brake is releasing on both rear tires. You will need to jack up the rear wheels to spin them by hand. A dragging rear brake will cause a pull.