Answer:
x ∈ (-9, 4]
Explanation:
The function changes sign where the binomial expressions change sign, at x = 4 and x = -9. For x > 4, both signs are positive. The signs will be different for -9 < x < 4. When the signs are different, the value of the function is negative, less than zero.
The function will be equal to zero at x = 4. There is a vertical asymptote at x = -9, so there is no zero at that point.
R(x) ≤ 0 for x ∈ (-9, 4].