Answer:
The factors of x² - 3·x - 18, are;
(x - 6), (x + 3)
Explanation:
The given quadratic expression is presented as follows;
x² - 3·x - 18
To factorize the given expression, we look for two numbers, which are the constant terms in the factors, such that the sum of the numbers is -3, while the product of the numbers is -18
By examination, we have the numbers -6, and 3, which gives;
-6 + 3 = -3
-6 × 3 = -18
Therefore, we can write;
x² - 3·x - 18 = (x - 6) × (x + 3)
Which gives;
(x - 6) × (x + 3) = x² + 3·x - 6·x - 18 = x² - 3·x - 18
Therefore, the factors of the expression, x² - 3·x - 18, are (x - 6) and (x + 3)