Answer:
D
Step-by-step explanation:
Since there are 3 excluded values then the denominator has to be of degree 3.
This excludes expressions B and C
Factor the denominators of expressions A and D
a³ - 15a² - 54a ← factor out a
= a(a² - 15a - 54) ← does not factor, thus not expression A
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a³ - 15a² + 54a ← factor out a
= a(a² - 15a + 54)
= a(a - 6)(a - 9) ← in factored form
The excluded values are therefore
a = 0, a = 6 and a = 9 → expression D
