If the demand for high-definition televisions increases, you can expect their price to

I would think increase seeing how they are in demand so that means very much wanted which means that would make them hustle and they would know that since people want their T. V's then they will buy them at a very very high price.

A classic case of supply and demand. If the demand for high-definition television increases, you can expect the price to also increase. If people really want an item, it’s likely that they would pay more for the popular item, since it is in such high demand.