20) After 8 hours, half of a 16-gram sample of a radioactive element remains. Find the constant k for this elemen -kt
hours, then use y = ne^kt to write the equation for modeling its exponential decay.

Which number is located at point a on the number line? a number line is shown from negative 10 to 10 with each interval mark on the number line representing one unit. point a is labeled one interval mark to the right of negative 5.