Question

Perfect square trinomial: (a – b)2 = (a – b)(a – b) = a2 – 2ab + b2 Find the product of (k – 9)2 using the perfect square trinomial rule shown on the left.

Answer 1

The product (k – 9)2 can also be written as (k-9)(k-9)

The product is k2 –18 k + 81

Explanation:

Answer 2

Substitute k for a, 9 for b.
(k - 9)² = k² - 2k×9 +9²
= k² -18k +81