Answer:
a = - 5, a = - 3
Step-by-step explanation:
Given
a² + 8a + 15 = 0 ← in standard form
(a + 3)(a + 5) = 0 ← in factored form
Equate each factor to zero and solve for a
a + 3 = 0 ⇒ a = - 3
a + 5 = 0 ⇒ a = - 5