Question

8 An expression for the product of two whole numbers is x2 - x - 20.

Write an expression for each of the whole numbers.​

Answer 1

(x - 5) and (x + 4)

Explanation:

To find the 2 numbers, factorise the given expression

Consider the factors of the constant term (- 20) which sum to give the coefficient of the x- term (- 1)

The factors are - 5 and + 4, since

- 5 × 4 = - 20 and - 5 + 4 = - 1, thus

x² - x - 20 = (x - 5)(x + 4)

The 2 numbers are x - 5 and x + 4