Question

Express d² - 8d + 9 in completed square form.​

Answer 1

(d - 4)² - 7

Explanation:

Formula for completing the square: x² + ax + b = (x +
`(a)/(2)`)² - (
`(a)/(2)`)² + b

d² - 8d + 9 = (d -
`(8)/(2)`)² - (
`(8)/(2)`)² + 9

= (d - 4)² - 4² + 9

= (d - 4)² - 16 + 9

= (d - 4)² - 7