Do you have to print out the tickets for the exhibit of King Tut or can I go in using my phone?

As long as you have the bar code I think you should be fine.

I was there last week and entered with the ticket saved on my phone. They scan the barcode from the phone.

Yes, phone works fine! My daughter had ours printed from the phone by the people in the box office, though, so I have it as a memento.

I am not sure. It doesn't say you can show the barcode. It specifically states to print at home. You may want to call them.