Will give brainliest if right, can someone help me with my math homework?

There were 816 people at a concert when a band started to play. after each song, only half the people stayed to hear the next song. how many people were left at the concert after x songs? write a function to represent this scenario.

The parabola y = x² - 4 opens: a.) up b.) down c.) right d.) left

A11 gram sample of a substance that’s used to treat thyroid disorders has a k-value of 0.1247