Answer:
Interval notation for range is (0, ∞)
Step-by-step explanation:
f(x)= 1/7 (9)^x

Range is the set of y values for which the function is defined
For all positive and negative values for x the value of y is always positive
so the range y value is greater than 0
Range of the function is y values greater than 0
y>0
Interval notation for range is (0, ∞)