Rubber straps with hooks on the ends are not a safe way to fasten something down. In an accident, anything in the car will be traveling forward with a force equal to its weight times the speed you are going. So if you were going 30 miles an an hour, your 10 pound TV will be moving with a force of 300 pounds. Rubber straps or bungee cords won't hold that much weight. If you can move the TV up by lifting it straight up (even if it's wedged and won't move any other direction), it will come out if your car rolls over.
Please, please, if you are traveling with a TV in your car, get one made for that purpose or use straps made to fasten things down in a vehicle. There are tie down straps that are made for securing things. They have non-stretchable straps and are made to be attached to a secure part of your car/van and cinched down into position so they can't stretch and won't move in an accident.