<h2>... Answer is in the pictures above... </h2><h3>... Hope this will help... </h3>
Answer:

Step-by-step explanation:
In this problem we have a exponential function of the form

where
f(x) is the remaining mass of the element in grams
x is the time in minutes
a is the initial value (y-intercept of the exponential function)
b is the base
r is the rate

In this problem we have

---> is negative because is a decay's rate

substitute
The exponential function is equal to

For x=15 minutes
substitute in the function


Answer:
d
Step-by-step explanation:
Answer:
yes
Step-by-step explanation:
the line is in -1 in all 4 quadrants, I will say yes but I'm not sure