Question

Factorise the following expression x² - 10 x + 21

Answer 1

(x-7)(x-3)

Explanation:

First, break down the factors of 21: 1, 3, 7, 21.

Because the product is positive, but the x's are negative, that means both will factorize to have a -.

Check the factor pairs to see which add up to 10.

3+7=10