Question

Which of the binomials below is a factor of this trinominal x^2-10x-39

A.)x+6
B.)x-6
C.)x-13
D.)x^2+13

Answer 1

C

Explanation:

To factorise the quadratic

Consider the factors of the constant term (- 39) which sum to give the coefficient of the x- term (- 10)

The factors are - 13 and + 3, since

- 13 × 3 = - 39 and - 13 + 3 = - 10, hence

x² - 10x - 39 = (x - 13)(x + 3) ← in factored form

x - 13 is a factor → C