Answer:
C
Step-by-step 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
