Answer:
x = - 5, x = 3
Explanation:
To find the x- intercepts let y = 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, hence
(x + 5)(x - 3) = 0
Equate each factor to zero and solve for x
x + 5 = 0 ⇒ x = - 5
x - 3 = 0 ⇒ x = 3
x- intercepts at (- 5, 0) and (3, 0)