Answer:
(x + 4)
Explanation:
By factoring the area expression we obtain the length, that is
x² - 3x - 28
Consider the factors of the constant term (- 28) which sum to give the coefficient of the x- term (- 3)
The factors are - 7 and + 4 , since
- 7 × 4 = - 28 and - 7 + 4 = - 3 , then
x² - 3x - 28 = (x - 7)(x + 4)
with width (x - 7) and length (x + 4)