Factor the trinomial 7x2 – 3x – 4. Which pair of numbers has a product of ac and a sum of b?

What is the factored form of the trinomial?

(x - 1)(7x + 4)

Step-by-step explanation:

Consider the factors of the product of the coefficient of the x² term and the constant term which sum to give the coefficient of the x- term.

product = 7 × - 4 = - 28 and sum = - 3

The factors are - 7 and + 4

Use these factors to split the x- term

7x² - 7x + 4x - 4 ( factor first/second and third/fourth terms )

= 7x(x - 1) + 4(x - 1) ← factor out (x - 1) from each term

= (x - 1)(7x + 4) ← in factored form