Which exponential function passes through the points (0, 21) and (1,3)?

Answer:
Option C
Explanation:
Given the following question:
Point A = (0, 21)
Point B = (1, 3)
In order to find the answer, we simply use the process of elimination and plot all the following functions in till we have our answer.
Option A:
[tex]7(\frac{1}{3} )^x[/tex]
After plotting the function, you will see that it does not in fact intercept at point B or (1, 3).
Option B:
[tex]7(\frac{1}{21} )^x[/tex]
After plotting the function, you will see that once again, it does not intercept at point B.
Option C:
[tex]21(\frac{1}{7} )^x[/tex]
After plotting the given function, you will see that not only does the line intercept at Point B or (1, 3), but it also intercepts at Point A or (0, 21)
Which means your answer is indeed option C.
Hope this helps.