The first thing we are going to do for this case is to rewrite the function.
We have then:
y = 3 ^ (2x)
We evaluate the points:
For (1,9):
y = 3 ^ (2 * 1)
y = 3 ^ (2)
y = 9
The point belongs to the function.
For (1/2, 3):
y = 3 ^ (2 * (1/2))
y = 3 ^ (1)
y = 3
The point belongs to the function.
For (-1, -9):
y = 3 ^ (2 * (- 1))
y = 3 ^ (- 2)
y = 1/9
The point does NOT belong to the function.
Answer:
The point (-1, -9) DOES NOT belong to the function.