Answer:
(a - 6)(a + 4)
Step-by-step explanation:
Consider the factors of the constant term (- 24) which sum to give the coefficient of the a- term (- 2)
The factors are - 6 and + 4, since
- 6 × 4 = - 24 and - 6 + 4 = - 2, thus
a² - 2a - 24 = (a - 6)(a + 4) ← in factored form