Answer:
x = - 5
Step-by-step explanation:
Given
f(x) =
The denominator of f(x) cannot be zero as this would make f(x) undefined. Equating the denominator to zero and solving gives the value that x cannot be.
solve : 3x + 15 = 0 ⇒ 3x = - 15 ⇒ x = - 5 ← excluded value
Domain x ∈ R , x ≠ - 5