Answer:
All the potential root of f(x) are
.
Step-by-step explanation:
According to the rational root theorem, all the potential root of f(x) are defined as

Where, p is factor of constant term and q is factor of leading coefficient.
The given function is

Here, constant term is 7 and leading coefficient is 9.
Factors of 7 are ±1, ±7 and the factors of 9 are ±1, ±3, ±9.
Using rational root theorem, all the potential root of f(x) are

Therefore all the potential root of f(x) are
.