Question

What number will make this expression a perfect square trinomial? Show your work.

x² - 6x + __

Answer 1

+ 9

Explanation:

given

x² - 6x

to make a perfect square use the method of completing the square

add ( half the coefficient of the x- term)² to x² - 6x

x² - 6x

= x² + 2(- 3)x + (- 3)²

= x² - 6x + 9

so

x² - 6x + 9 = (x - 3)² ← a perfect square