Answer:
(- 3, 0 ) and (5, 0 )
Step-by-step explanation:
To find the x- intercepts let f(x) = 0 , that is
x² - 2x - 15 = 0
Consider the factors of the constant term (- 15) which sum to give the coefficient of the x- term (- 2)
The factors are - 5 and + 3 , since
- 5 × 3 = - 15 and - 5 + 3 = - 2 , then
(x - 5)(x + 3) = 0 ← in factored form
Equate each factor to zero and solve for x
x - 5 = 0 ⇒ x = 5
x + 3 = 0 ⇒ x = - 3
The x- intercepts are (- 3, 0 ) and (5, 0 )
