Answer:
x = 2, x = 4
Explanation:
Begin by letting f(x) = 0 , that is
x² - 6x + 8 = 0
Consider the factors of the constant term (+ 8) which sum to give the coefficient of the x- term (- 6)
The factors are - 2 and - 4 , since
- 2 × - 4 = + 8 and - 2 - 4 = - 6 , then
(x - 2)(x - 4) = 0
Equate each factor to zero and solve for x
x - 2 = 0 ⇒ x = 2
x - 4 = 0 ⇒ x = 4