Which of the following points is not on the graph of y=3(1/2)^x
a.
(–2, 12)
b.
(3,3/8)
c.
(0, 3)
d.
(–1, 9)

In order to solve this problem, you have to substitute x and y for each coordinate pair. which ever pair doesn't work with the equation is the answer.

y=3(1/2)^x
12=3(1/2)^-2    12=3(4)   12=12 (correct)
3/8=3(1/2)^3     3/8=3(1/8)   3/8=3/8 (correct)
3=3(1/2)^0        3=3(1)      3=3 (correct)
9=3(1/2)^-1      9=3(2)     9=6 (incorrect)

because 9≠6 we can see that (-1, 9) is the point that does not lie on the graphed equation