Answer:
(x - 7)(x - 3)
Step-by-step explanation:
Given
x² - 10x + 21
Consider the factors of the constant term (+ 21) which sum to give the coefficient of the x- term (- 10)
The factors are - 7 and - 3, since
- 7 × - 3 = + 21 and - 7 - 3 = - 10 , thus
x² - 10x + 21 = (x - 7)(x - 3)
