Answer: the answer is 4
Step-by-step explanation:
when looking for the half life, it says to look for when the initial amount is half of what it used to be, because it is 100, 100 divided by 2 is 50, and when looking at the hours (x value) for 50 it says 4.
You’re answer is 21
7(3)= 21 I hope I’m right :))
