rear tires slanted, wearing out on the inside. what causes this.

The wheels on this vehicle all can be adjusted for wheel alignment. Have a four wheel alignment professionally performed using a suitable alignment rack and machine. If any of the wheels are so far out of proper specification that it becomes difficult to successfully perform the wheel alignment, the affected wheel and axle should be inspected more closely for possible bent components. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops