Question

Factor the expression below.

x2 - 6x + 9
A.
(x + 3)(x + 3)
B.
3(x2 - 2x + 3)
OC. (x-3)(x-3)
OD.
(x - 3)(x + 3)
HELP

Answer 1

Answer: (x-3)(x-3)

This is a perfect square trinomial in the form a^2 - 2ab + b^2 = (a-b)^2. In this case, a = x and b = -3.

Another way you can look at it is to ask yourself "what two numbers multiply to 9 (last term) and add to -6 (middle coefficient)?". Those two numbers are -3 and -3

-3 plus -3 = -6

-3 times -3 = 9

So this is why x^2-6x+9 = (x-3)(x-3)

We can expand (x-3)(x-3) back out to get x^2-6x+9 again using the FOIL rule, distributive property, or the box method.

Answer 2

C. (x-3)(x-3)

Explanation:

x² - 6x + 9 = 0

x² - 3x - 3x + 9 = 0

x(x - 3) - 3(x - 3) = 0

(x - 3) (x - 3) = 0