X2 - 15x + 56

factor

(x - 7) (x - 8)

Step-by-step explanation:

To factorise the quadratic

Consider the factors of the constant term ( + 56) which sum to give the coefficient of the x - term ( - 15)

The factors are - 7 and - 8, since

- 7 * - 8 = + 56 and - 7 - 8 = - 15, hence

x² - 15x + 56 = (x - 7) (x - 8)