Question

analyzing key features of exponential functions
the table shows the decay rate for a certain radioactive material over time. in this context, what does the y - intercept represent?
at 100 hours, there are 0 grams of the substance remaining.
at 100 hours, there are 100 grams of the substance remaining.
at 0 hours, there are 100 grams of the substance remaining.
at 0 hours, there is 1 gram of the substance remaining.

Explanation:

The y - intercept of a function occurs when the independent variable (in this case time $t = 0$). Looking at the table, when time (in hours) is 0, the amount of substance remaining is 100 grams.

Answer:

At 0 hours, there are 100 grams of the substance remaining.